Signal amplifier works

Phil Hobbs · Feb 11, 2013

On 02/11/2013 02:42 PM, Uncle Steve wrote:

On Mon, Feb 11, 2013 at 11:21:40AM -0500, Phil Hobbs wrote:
On 02/11/2013 04:43 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:
On 2/10/2013 10:44 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:
On 2/9/2013 9:55 PM, John Larkin wrote:
On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve<stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy is
smarmy besides, coming over all superior about current flow vs electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to deliver
some power to the speaker as in figure 16. I have different parts on
hand, and I am working with a 12V supply instead of 9V as in the first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
|> R2> R3 | R3 = 220
R1> < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

They're all conspiring against you.

Only the retard, righttards, and related degenerates and defectives.
Oftentimes they believe (with no evidence) that their mindset is
exclusive to the world's population, but in actual point of fact they
pretend that sensible, rational, normal folk don't exist and only
those with their special brand of prejudice are 'people'. They are
easily identifiable by their myopic insistance that reality must
conform to their view of it, or at least what little of it they
acknowledge.

It's all so tiresome. Greg Egan once wrote of a hypothetical
terrorist group described as "anthrocosmologists" who bear a striking
resemblance to such persons, who impute anthropic principles to
existence a priori -- which is necessarily the opposite to the idea of
undertaking observation to deduce or infer principles of existence.
The sick joke is that this retrograde method of apprehending reality
is called 'knowing' among people of that sort. To 'know' is to bring
an aspect of reality into existence, in contrast to the usual process
of knowledge acquisition normal to scientific pursuit. Losers.

Ohh-kay then. (Smiles, nods, and creeps out the padded cell door,
locking it behind him.)

Phil Hobbs

Jamie · Feb 11, 2013

Uncle Steve wrote:

On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:

On 2/10/2013 10:44 AM, Uncle Steve wrote:

On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:

On 2/9/2013 9:55 PM, John Larkin wrote:

On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve <stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy is
smarmy besides, coming over all superior about current flow vs electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to deliver
some power to the speaker as in figure 16. I have different parts on
hand, and I am working with a 12V supply instead of 9V as in the first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
| > R2 > R3 | R3 = 220
R1 > < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

Competition?

Jamie

Uncle Steve · Feb 11, 2013

On Mon, Feb 11, 2013 at 03:55:16PM -0500, Phil Hobbs wrote:

On 02/11/2013 02:42 PM, Uncle Steve wrote:
On Mon, Feb 11, 2013 at 11:21:40AM -0500, Phil Hobbs wrote:
On 02/11/2013 04:43 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:
On 2/10/2013 10:44 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:
On 2/9/2013 9:55 PM, John Larkin wrote:
On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve<stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy
is
smarmy besides, coming over all superior about current flow vs
electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to
deliver
some power to the speaker as in figure 16. I have different parts
on
hand, and I am working with a 12V supply instead of 9V as in the
first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
|> R2> R3 | R3 = 220
R1> < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

They're all conspiring against you.

Only the retard, righttards, and related degenerates and defectives.
Oftentimes they believe (with no evidence) that their mindset is
exclusive to the world's population, but in actual point of fact they
pretend that sensible, rational, normal folk don't exist and only
those with their special brand of prejudice are 'people'. They are
easily identifiable by their myopic insistance that reality must
conform to their view of it, or at least what little of it they
acknowledge.

It's all so tiresome. Greg Egan once wrote of a hypothetical
terrorist group described as "anthrocosmologists" who bear a striking
resemblance to such persons, who impute anthropic principles to
existence a priori -- which is necessarily the opposite to the idea of
undertaking observation to deduce or infer principles of existence.
The sick joke is that this retrograde method of apprehending reality
is called 'knowing' among people of that sort. To 'know' is to bring
an aspect of reality into existence, in contrast to the usual process
of knowledge acquisition normal to scientific pursuit. Losers.

Ohh-kay then. (Smiles, nods, and creeps out the padded cell door,
locking it behind him.)

Are you attempting to say you don't agree with my take on the
righttard way of 'knowing'?

Regards,

Uncle Steve

--
More than a century has passed since science laid down sound
propositions as to the origins of the universe, but how many have
mastered them or possess the really scientific spirit of criticism? A
few thousands at the outside, who are lost in the midst of hundreds of
millions still steeped in prejudices and superstitions worthy of
savages, who are consequently ever ready to serve as puppets for
religious impostors. -- Peter Kropotkin

Uncle Steve · Feb 11, 2013

On Mon, Feb 11, 2013 at 05:53:04PM -0500, Jamie wrote:

Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:

On 2/10/2013 10:44 AM, Uncle Steve wrote:

On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:

On 2/9/2013 9:55 PM, John Larkin wrote:

On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve <stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy is
smarmy besides, coming over all superior about current flow vs electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to deliver
some power to the speaker as in figure 16. I have different parts on
hand, and I am working with a 12V supply instead of 9V as in the first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
| > R2 > R3 | R3 = 220
R1 > < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

Competition?

What, they want to sell me a fish every day? I can catch my own
goddamn fish.

Regards,

Uncle Steve

--
More than a century has passed since science laid down sound
propositions as to the origins of the universe, but how many have
mastered them or possess the really scientific spirit of criticism? A
few thousands at the outside, who are lost in the midst of hundreds of
millions still steeped in prejudices and superstitions worthy of
savages, who are consequently ever ready to serve as puppets for
religious impostors. -- Peter Kropotkin

Michael A. Terrell · Feb 12, 2013

Uncle Steve wrote:

so tiresome.

Feb 12, 2013

On Mon, 11 Feb 2013 18:53:06 -0500, Uncle Steve <stevet810@gmail.com>
wrote:

On Mon, Feb 11, 2013 at 05:53:04PM -0500, Jamie wrote:
Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:

On 2/10/2013 10:44 AM, Uncle Steve wrote:

On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:

On 2/9/2013 9:55 PM, John Larkin wrote:

On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve <stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy is
smarmy besides, coming over all superior about current flow vs electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to deliver
some power to the speaker as in figure 16. I have different parts on
hand, and I am working with a 12V supply instead of 9V as in the first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
| > R2 > R3 | R3 = 220
R1 > < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

Competition?

What, they want to sell me a fish every day? I can catch my own
goddamn fish.

Yet you expect people to go out of their way to teach you to fish
after you've pissed on them. That is the lefty way.

Uncle Steve · Feb 12, 2013

On Mon, Feb 11, 2013 at 07:24:37PM -0500, krw@attt.bizz wrote:

On Mon, 11 Feb 2013 18:53:06 -0500, Uncle Steve <stevet810@gmail.com
wrote:

On Mon, Feb 11, 2013 at 05:53:04PM -0500, Jamie wrote:
Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:

On 2/10/2013 10:44 AM, Uncle Steve wrote:

On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:

On 2/9/2013 9:55 PM, John Larkin wrote:

On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve <stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy is
smarmy besides, coming over all superior about current flow vs electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to deliver
some power to the speaker as in figure 16. I have different parts on
hand, and I am working with a 12V supply instead of 9V as in the first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
| > R2 > R3 | R3 = 220
R1 > < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

Competition?

What, they want to sell me a fish every day? I can catch my own
goddamn fish.

Yet you expect people to go out of their way to teach you to fish
after you've pissed on them. That is the lefty way.

No, I merely expect that sane people won't lie or distort facts merely
because they think that knowledge is sacred and requires some sort of
arbitrary sacrifice to be paid in return for its disclosure. If you
think the 'payment' for discussion of the trivial is measured in
humiliation, you are insane.

Regards,

Uncle Steve

--
More than a century has passed since science laid down sound
propositions as to the origins of the universe, but how many have
mastered them or possess the really scientific spirit of criticism? A
few thousands at the outside, who are lost in the midst of hundreds of
millions still steeped in prejudices and superstitions worthy of
savages, who are consequently ever ready to serve as puppets for
religious impostors. -- Peter Kropotkin

Jamie · Feb 12, 2013

Uncle Steve wrote:

On Mon, Feb 11, 2013 at 07:24:37PM -0500, krw@attt.bizz wrote:

On Mon, 11 Feb 2013 18:53:06 -0500, Uncle Steve <stevet810@gmail.com
wrote:

On Mon, Feb 11, 2013 at 05:53:04PM -0500, Jamie wrote:

Uncle Steve wrote:

On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:

On 2/10/2013 10:44 AM, Uncle Steve wrote:

On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:

On 2/9/2013 9:55 PM, John Larkin wrote:

On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve <stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy is
smarmy besides, coming over all superior about current flow vs electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to deliver
some power to the speaker as in figure 16. I have different parts on
hand, and I am working with a 12V supply instead of 9V as in the first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
| > R2 > R3 | R3 = 220
R1 > < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

Competition?

What, they want to sell me a fish every day? I can catch my own
goddamn fish.

Yet you expect people to go out of their way to teach you to fish
after you've pissed on them. That is the lefty way.

No, I merely expect that sane people won't lie or distort facts merely
because they think that knowledge is sacred and requires some sort of
arbitrary sacrifice to be paid in return for its disclosure. If you
think the 'payment' for discussion of the trivial is measured in
humiliation, you are insane.

Regards,

Uncle Steve

http://www.youtube.com/watch?v=n-RVwILsb9o

Jamie

Jim Thompson · Feb 12, 2013

On Mon, 11 Feb 2013 18:51:31 -0500, Uncle Steve <stevet810@gmail.com>
wrote:

On Mon, Feb 11, 2013 at 03:55:16PM -0500, Phil Hobbs wrote:
On 02/11/2013 02:42 PM, Uncle Steve wrote:
On Mon, Feb 11, 2013 at 11:21:40AM -0500, Phil Hobbs wrote:
On 02/11/2013 04:43 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:
On 2/10/2013 10:44 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:
On 2/9/2013 9:55 PM, John Larkin wrote:
On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve<stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy
is
smarmy besides, coming over all superior about current flow vs
electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to
deliver
some power to the speaker as in figure 16. I have different parts
on
hand, and I am working with a 12V supply instead of 9V as in the
first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
|> R2> R3 | R3 = 220
R1> < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

They're all conspiring against you.

Only the retard, righttards, and related degenerates and defectives.
Oftentimes they believe (with no evidence) that their mindset is
exclusive to the world's population, but in actual point of fact they
pretend that sensible, rational, normal folk don't exist and only
those with their special brand of prejudice are 'people'. They are
easily identifiable by their myopic insistance that reality must
conform to their view of it, or at least what little of it they
acknowledge.

It's all so tiresome. Greg Egan once wrote of a hypothetical
terrorist group described as "anthrocosmologists" who bear a striking
resemblance to such persons, who impute anthropic principles to
existence a priori -- which is necessarily the opposite to the idea of
undertaking observation to deduce or infer principles of existence.
The sick joke is that this retrograde method of apprehending reality
is called 'knowing' among people of that sort. To 'know' is to bring
an aspect of reality into existence, in contrast to the usual process
of knowledge acquisition normal to scientific pursuit. Losers.

Ohh-kay then. (Smiles, nods, and creeps out the padded cell door,
locking it behind him.)

Are you attempting to say you don't agree with my take on the
righttard way of 'knowing'?

Regards,

Uncle Steve

Michael A. Terrell · Feb 12, 2013

Jim Thompson wrote:

Uncle Steve wrote:

Are you attempting to say you don't agree with my take on the
righttard way of 'knowing'?

Anyone who uses 'righttard' is beyond help if the answer isn't part
of the DNC mantra, or his well worn KKK handbook.

Nope. We're just saying there's no chance in hell you'll EVER learn
circuit design.

He's like the knuckle dragging moron on "Big bang Theory" who said,
"That's what I lie about science. There's not just one right answer."
He doesn't know a damn thing, yet he thinks he matters.

As that great Texas sage Ron White says, "You can't cure stupid.
Stupid is forever."

Bob Masta · Feb 12, 2013

On Sun, 10 Feb 2013 09:37:03 -0500, Uncle Steve
<stevet810@gmail.com> wrote:

On Sun, Feb 10, 2013 at 01:51:48PM +0000, Bob Masta wrote:
On Sat, 09 Feb 2013 15:38:15 -0500, Uncle Steve
stevet810@gmail.com> wrote:

On Fri, Feb 08, 2013 at 09:01:39PM -0800, Jon Kirwan wrote:
On Fri, 08 Feb 2013 21:18:13 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

big snip of everything

You forgot the bootstrap effect >:-}

...Jim Thompson

I didn't miss out on the "Negative Feedback in Audio
Amplifiers" thread. But since this is posted in .basics it
seems appropriate to put on the kid gloves. There's still
plenty of time to add in a bootstrap, too!

I've still got an audio power amp that's better than my somewhat
expensive speakers. Haven't blown that up yet.

OK, I've just got to ask: Why not simply use the power amp
to drive the tweeter? The amp frequency response may not be
flat to 50 kHz, but you don't need that here. The amp
probably puts out something like +/-20V, so 50 kHz can be
well down on the roll-off and you'll still have plenty of
moxie to fry your tweeter. (And if you are only trying to
use a frequency high enough to be inaudible, something
closer to 20 kHz will probably be just fine too... unless
you are a very precocious child, or you eat a lot of dog
food.)

ATM, I only have one amplifier and preamplifier and basically, I would
prefer to learn something rather than throw money at the problem.
Analog electronics is on my 'to-do' list, which I why I purchased a
scope and some parts a little while ago. In fact, I'm more interested
in embedded systems programming, but of course analog electronics is
how those things interface with the real world.

OK, maybe you don't want to pull the amp from the stereo
installation, if you expect the tweeter development to take
a long time, and you want to listen to music before it's
done. In that case, you can build a pretty decent power amp
using quasi-complimentary 2055s (or any other NPN power
type). You use one in a more-or-less conventional
Darlington with a small-signal NPN drive, and the other with
a PNP driver.

This configuration was pretty standard before decent
complimentary power pairs became readily available. I
imagine that Googling on "quasi-complimentary power amp"
will get you lots of circuits. When true complimentary
pairs arrived, quasi-comp got a lot of bad press. But the
old design wasn't really bad: Back in 1973 I made a unit
using an old Delco Radio app note and subbed 2N3055s for
their part, and at 40 watts per channel into 8 ohms it had
0.06% THD at 1 kHz, rising to less than 0.2% at 20 kHz.
(Tested by Marantz techs at a local stereo store, on tour
with a rack of test equipment to demonstrate how much better
Marantz was than whatever you brought in. We each got a
nifty test results certificate with THD plot of our amps to
take home.)

The tweeter development is done for all intents and purposes. The
tooling to cut and form the ribbon is made, so I can turn out
nominally identical parts with relatively little effort. The
amplifier is really only needed to break it in a little (mostly
important for a thicker material than what I am using currently),
which can be done in-system but I was getting tired of swapping
tweeters and listening to crap sound while experimenting.

It looks as though I just need to find some electronics basics
tutorials that will impart the knowledge I need to acquire, as opposed
to bogus sites that contain lots of misleading information. Once upon
a time I had a copy of TAOE, but lost it due to circumstanced beyond
my control, and before I had time to study it much. I'm sure I'll
figure something out before long; after all this isn't rocket science.

For educational purposes as well as tweeter break-in, here
is a good compromise solution: Use an op-amp for the front
end of your power amp, and just build the power output
stage. I'd recommend using a "real" op-amp, even a lowly
741, on separate pos and neg supplies. The single-supply
units tend to be much more difficult to apply for decent
audio, and you don't need that kind of distraction just yet.

Note also that traditional (ie not class D sitiching) audio
power amps are really just op-amp circuits with beefy output
stages. Once you get the the output working, you can think
about delving into the differential input stuff, if you
want.

So the basic idea is to first wire up a simple single op-amp
stage. It can be inverting or non-inverting, though real
audio power amps are almost always non-inverting. Get it to
drive a dummy load of (say) 1-10k or so, viewed on your
scope to see that it's working properly.

Now add the output stage. You can use a simple (but
terribly inefficient) class A output. Break the connection
at the op-amp output pin, so the op-amp is on one side and
the feedback and load are on the other.. Connect up your
NPN power (2N3055) base to the op-amp, emitter to neg
supply, collector to the feedback and load. Also to the
collector you need a power resistor to the pos supply. The
value should be computed so that when the NPN is off, the R
will be able to supply the actual (8 ohm or whatever) load
at the max positive swing.

The output stage doesn't need to use the same power supplies
as the op-amp, for instance if you have only low-current
regulated supplies for the op-amp, you can use totally
unregulated high-current supplies for the output. (Real
power amps typically don't use separate regulated supplies
at all, the whole shebang runs off the big unregulated
supplies. But in your case you have to observe the voltage
limits of the op-amp, typically +/-15. If you have
unregulated supplies that stay below that, use them for
everything.)

Next step: If you have a PNP power device, you can easily
make this into a class B stage. Just replace the R between
the NPN collector and pos supply with the PNP. The PNP
collector goes to the NPN collector/load/feedback
connection, the emitter to V+, the base to the NPN
base/op-amp output.

This will be much more efficient, and would be ideal for
your break-in purposes. The reason you don't see this true
class B in real audio is that it has crossover distortion.
At signal voltages near zero, both transistors "want" to be
off. They each need several tenths of a volt to get going,
but they need opposite polarities to do so... a problem
since their bases are connected together. The huge internal
gain of the op-amp can deal with this *fairly* well, since
when the load needs to be (say) -0.1 V, it can apply -0.6 V
(or whatever it takes) to the base to get the NPN to go on.
But there are limits to how well it can do this, and you
notice them at really low signal levels... not a problem at
all for your break-in job.

True audio amps are typically class AB, which applies a bias
to each output device to keep it out of the fully-off state
near zero. This can be tricky, since it means both devices
are on at the same time, and if you apply too much bias you
can easily get them both hot enough to enter thermal
runaway: A bit more heat causes more current to flow, which
causes more heat.... (Bipolar devices have this problem,
but not FETs, which is one reason why modern amps use
FETs.)

Hope this helps!

Best regards,

Bob Masta

DAQARTA v7.21
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!

Uncle Steve · Feb 12, 2013

On Mon, Feb 11, 2013 at 07:28:14PM -0700, Jim Thompson wrote:

On Mon, 11 Feb 2013 18:51:31 -0500, Uncle Steve <stevet810@gmail.com
wrote:

On Mon, Feb 11, 2013 at 03:55:16PM -0500, Phil Hobbs wrote:
On 02/11/2013 02:42 PM, Uncle Steve wrote:
On Mon, Feb 11, 2013 at 11:21:40AM -0500, Phil Hobbs wrote:
On 02/11/2013 04:43 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:
On 2/10/2013 10:44 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:
On 2/9/2013 9:55 PM, John Larkin wrote:
On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve<stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy
is
smarmy besides, coming over all superior about current flow vs
electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to
deliver
some power to the speaker as in figure 16. I have different parts
on
hand, and I am working with a 12V supply instead of 9V as in the
first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
|> R2> R3 | R3 = 220
R1> < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

They're all conspiring against you.

Only the retard, righttards, and related degenerates and defectives.
Oftentimes they believe (with no evidence) that their mindset is
exclusive to the world's population, but in actual point of fact they
pretend that sensible, rational, normal folk don't exist and only
those with their special brand of prejudice are 'people'. They are
easily identifiable by their myopic insistance that reality must
conform to their view of it, or at least what little of it they
acknowledge.

It's all so tiresome. Greg Egan once wrote of a hypothetical
terrorist group described as "anthrocosmologists" who bear a striking
resemblance to such persons, who impute anthropic principles to
existence a priori -- which is necessarily the opposite to the idea of
undertaking observation to deduce or infer principles of existence.
The sick joke is that this retrograde method of apprehending reality
is called 'knowing' among people of that sort. To 'know' is to bring
an aspect of reality into existence, in contrast to the usual process
of knowledge acquisition normal to scientific pursuit. Losers.

Ohh-kay then. (Smiles, nods, and creeps out the padded cell door,
locking it behind him.)

Are you attempting to say you don't agree with my take on the
righttard way of 'knowing'?

Regards,

Uncle Steve

Nope. We're just saying there's no chance in hell you'll EVER learn
circuit design.

As that great Texas sage Ron White says, "You can't cure stupid.
Stupid is forever."

Congratulations. You have won the discussion without sullying your
argument with the faintest hint of a fact.

It is so helpful when you losers play your cards so quickly, making
the inevitable 'plonk' decision that much simpler. Some of your
marginally more intelligent peers are able to dissemble for days, even
weeks before showing their true colours.

So. Anyone else want to step up and practice your logical and
argumentative fallacies?

Regards,

Uncle Steve

--
More than a century has passed since science laid down sound
propositions as to the origins of the universe, but how many have
mastered them or possess the really scientific spirit of criticism? A
few thousands at the outside, who are lost in the midst of hundreds of
millions still steeped in prejudices and superstitions worthy of
savages, who are consequently ever ready to serve as puppets for
religious impostors. -- Peter Kropotkin

Uncle Steve · Feb 12, 2013

On Mon, Feb 11, 2013 at 11:49:46PM -0500, Michael A. Terrell wrote:

Jim Thompson wrote:

Uncle Steve wrote:

Are you attempting to say you don't agree with my take on the
righttard way of 'knowing'?

Anyone who uses 'righttard' is beyond help if the answer isn't part
of the DNC mantra, or his well worn KKK handbook.

You're well known in other newsgroups as invincibly ignorant, so I
suppose you may as well join "Joe Thompson" in the bozo bin. I'm sure
you will be able to constructively occupy your time there with
characteristic self-congratulatory self-promotion, secure in the
knowledge that you're right and everyone else is wrong if they dare
disagree.

Nope. We're just saying there's no chance in hell you'll EVER learn
circuit design.

He's like the knuckle dragging moron on "Big bang Theory" who said,
"That's what I lie about science. There's not just one right answer."
He doesn't know a damn thing, yet he thinks he matters.

As much as I'd love to compare our vast ignorance on every topic
imaginable, I will happily cede that field to you.

Regards,

Uncle Steve

--
More than a century has passed since science laid down sound
propositions as to the origins of the universe, but how many have
mastered them or possess the really scientific spirit of criticism? A
few thousands at the outside, who are lost in the midst of hundreds of
millions still steeped in prejudices and superstitions worthy of
savages, who are consequently ever ready to serve as puppets for
religious impostors. -- Peter Kropotkin

Uncle Steve · Feb 12, 2013

On Tue, Feb 12, 2013 at 01:50:32PM +0000, Bob Masta wrote:

On Sun, 10 Feb 2013 09:37:03 -0500, Uncle Steve
stevet810@gmail.com> wrote:

On Sun, Feb 10, 2013 at 01:51:48PM +0000, Bob Masta wrote:
On Sat, 09 Feb 2013 15:38:15 -0500, Uncle Steve
stevet810@gmail.com> wrote:

For educational purposes as well as tweeter break-in, here
is a good compromise solution: Use an op-amp for the front
end of your power amp, and just build the power output
stage. I'd recommend using a "real" op-amp, even a lowly
741, on separate pos and neg supplies. The single-supply
units tend to be much more difficult to apply for decent
audio, and you don't need that kind of distraction just yet.

I may end up doing this, although I am still inclined to see what I
can do with what I have on-hand. What did everyone do before op-amps
were available?

Note also that traditional (ie not class D sitiching) audio
power amps are really just op-amp circuits with beefy output
stages. Once you get the the output working, you can think
about delving into the differential input stuff, if you
want.

http://sound.westhost.com/project36.htm has a reasonably detailed
home-brew project covering some of its development and testing.
Figure three slightly resembles what I was initially working with, and
figure four describes a complete solution, which may be adequate for
my purposes.

So the basic idea is to first wire up a simple single op-amp
stage. It can be inverting or non-inverting, though real
audio power amps are almost always non-inverting. Get it to
drive a dummy load of (say) 1-10k or so, viewed on your
scope to see that it's working properly.

The first thing I'm going to do is understand R/C networks better.
The thing that's confusing me at the moment is the frequency-variance
of circuits under load. I'm still coming to grips with the
non-linearity of electronics, which essentially doesn't exist in
computer programming.

Now add the output stage. You can use a simple (but
terribly inefficient) class A output. Break the connection
at the op-amp output pin, so the op-amp is on one side and
the feedback and load are on the other.. Connect up your
NPN power (2N3055) base to the op-amp, emitter to neg
supply, collector to the feedback and load. Also to the
collector you need a power resistor to the pos supply. The
value should be computed so that when the NPN is off, the R
will be able to supply the actual (8 ohm or whatever) load
at the max positive swing.

With you so far.

The output stage doesn't need to use the same power supplies
as the op-amp, for instance if you have only low-current
regulated supplies for the op-amp, you can use totally
unregulated high-current supplies for the output. (Real
power amps typically don't use separate regulated supplies
at all, the whole shebang runs off the big unregulated
supplies. But in your case you have to observe the voltage
limits of the op-amp, typically +/-15. If you have
unregulated supplies that stay below that, use them for
everything.)

You mean to say run the input stage off the low-power regulated supply
and the output stage right off a bridge rectifier. Perhaps that is a
good idea. I'm kicking myself at the moment for only picking up only
one 12V torroidial transformer from the local surplus shop. If i had
two, it would make a really beefy 24V supply. The 12V supply I was
using is a much smaller wall-tumor (about 1A) that may have been
struggling to heat up the original circuit. I was watching the P/S
led on the regulated side fade out as thermal runaway got going.

Next step: If you have a PNP power device, you can easily
make this into a class B stage. Just replace the R between
the NPN collector and pos supply with the PNP. The PNP
collector goes to the NPN collector/load/feedback
connection, the emitter to V+, the base to the NPN
base/op-amp output.

This will be much more efficient, and would be ideal for
your break-in purposes. The reason you don't see this true
class B in real audio is that it has crossover distortion.
At signal voltages near zero, both transistors "want" to be
off. They each need several tenths of a volt to get going,
but they need opposite polarities to do so... a problem
since their bases are connected together. The huge internal
gain of the op-amp can deal with this *fairly* well, since
when the load needs to be (say) -0.1 V, it can apply -0.6 V
(or whatever it takes) to the base to get the NPN to go on.
But there are limits to how well it can do this, and you
notice them at really low signal levels... not a problem at
all for your break-in job.

True enough, most audio listening happens at power levels that should
be a fraction of rated power. In this case, the driver is going to be
beating against a bag of cotton balls or similar, and I don't give a
rat's ass about THD. I've seen a few amp circuits with a NPN/PNP pair
as you describe. I suppose it requires more negative feedback than
otherwise to counteract the low-level distortion.

True audio amps are typically class AB, which applies a bias
to each output device to keep it out of the fully-off state
near zero. This can be tricky, since it means both devices
are on at the same time, and if you apply too much bias you
can easily get them both hot enough to enter thermal
runaway: A bit more heat causes more current to flow, which
causes more heat.... (Bipolar devices have this problem,
but not FETs, which is one reason why modern amps use
FETs.)

Does that mean the bias causes the two output devices will fight each
other to stay near their turn-on threshold? As I said, this
application is specific enough that signal distortion is really not a
problem at the target output power. If there's 5% distortion, the
only thing that's going to notice is the cotton-balls absorbing driver
output.

Hope this helps!

I clarifies some of the web-material I've read. Thank you.

Regards,

Uncle Steve

--
More than a century has passed since science laid down sound
propositions as to the origins of the universe, but how many have
mastered them or possess the really scientific spirit of criticism? A
few thousands at the outside, who are lost in the midst of hundreds of
millions still steeped in prejudices and superstitions worthy of
savages, who are consequently ever ready to serve as puppets for
religious impostors. -- Peter Kropotkin

Jim Thompson · Feb 12, 2013

On Tue, 12 Feb 2013 12:59:12 -0500, Uncle Steve <stevet810@gmail.com>
wrote:

On Mon, Feb 11, 2013 at 07:28:14PM -0700, Jim Thompson wrote:
On Mon, 11 Feb 2013 18:51:31 -0500, Uncle Steve <stevet810@gmail.com
wrote:

On Mon, Feb 11, 2013 at 03:55:16PM -0500, Phil Hobbs wrote:
On 02/11/2013 02:42 PM, Uncle Steve wrote:
On Mon, Feb 11, 2013 at 11:21:40AM -0500, Phil Hobbs wrote:
On 02/11/2013 04:43 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 01:49:20PM -0500, Phil Hobbs wrote:
On 2/10/2013 10:44 AM, Uncle Steve wrote:
On Sun, Feb 10, 2013 at 10:18:13AM -0500, Phil Hobbs wrote:
On 2/9/2013 9:55 PM, John Larkin wrote:
On Fri, 08 Feb 2013 14:14:08 -0500, Uncle Steve<stevet810@gmail.com
wrote:

... unless there is no signal at the input.

I started with some information at the following two URLS:

http://www.mysticmarvels.com/amplifier.html
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html

Sorry, they are both hacks and idiots, the first one being the worst.

Yup, both full of Bad Info presented with confidence. The first guy
is
smarmy besides, coming over all superior about current flow vs
electron
flow, as if it mattered for solid-state circuit design.

That little tidbit is useful. As electrons are the medium of
electronic signal propagation, it's helpful to know what's actually
going on in the wires. Counter-intuitive concepts like that are
exactly the sort of thing that make science difficult for kids. An
exemplar is the view of the Earth as the center of the universe, as
was common knowledge prior to the Copernican revolution.

It's a good thing to know, but reversing the directions of all the
arrows in his diagrams is going to confuse people terminally when they
get to real circuit design. The main point of drawing diagrams so that
current flows generally downward and to the right is so that people
don't get confused, and to reduce the number of minus signs in the
algebra, which of course are a common source of blunders.

The less obvious advantage to the current convention is that it makes
electronic diagrams more amenable to stand-in as loose metaphor for
life, or living, but it is difficult to explain since 'living' in this
context is a religious concept subject to the usual prohibitions on
open discussion or analysis.

Counterfactual concepts make real understanding unnecessarily
difficult. The fact that electronic circuits are presented with the
assumption that charge flows from positive to negative poles obscures
the idea that it is the electrical potential for the flow of electrons
that is significant at any given point in a circuit. I don't doubt
that the terminology in common use could be less confusing.

Do you have an example of a solid-state circuit accessible to a beginner
where it matters what the carrier polarity is? Holes are slower than
electrons in almost every material I can think of, but they look like
perfectly good positive charge carriers in all other respects.

The first URL goes through the process of building a high-gain
amplifier, and it works O.K. with the exception that there is no
power. The second URL goes into more detail and shows how to
deliver
some power to the speaker as in figure 16. I have different parts
on
hand, and I am working with a 12V supply instead of 9V as in the
first
URL. Since I am looking to deliver big chunky volts to my speaker,
I went ahead and modified Figure 16 and the example in the first URL
to obtain the following circuit:

12V +---+----------+----------+ R1 = 510K
| | | | R2 = 5.9K
|> R2> R3 | R3 = 220
R1> < < | C1 = 1uF
| | | Q1, Q2 = 2N2222
| +-- | | Q3 = 2N3055
input | | \ b |c |
o---||-+-(Q1) -----(Q2) -----(Q3)
C1 | |e / |
1uf | --- SPKR
| |
| |
o----------+---------------------+

SPKR is a ribbon tweeter with a 2 Ohm, 10 Watt resistor in series.

Yikes, Beta bias! DC through the voice coil!

That looks a lot like a circuit that I built when I was 10, out of a
book of projects (that would have been early 1970). It sorta worked,
kinda, but ate batteries like mad. (It used a TR01C TO-3 package
germanium transistor, made by International Rectifier. It also had a
carbon mic so it didn't need a preamp.)

I'll be better off when I internalize the details of how transistors
work in various configurations, but at the moment the concepts are
still a little fuzzy.

Sure, it takes everybody awhile--they're nontrivial devices. It's
easier to get right if you think of transistors as mostly
voltage-controlled rather than current-controlled. That's closer to the
physics, and will also protect you against doing beta-dependent circuits
like the above and the ones in reference #2.

Base current isn't a necessary feature of transistor behaviour--you can
get transistors with betas ranging from about 5 to several thousand, and
the beta of a single device can easily vary over a 3:1 range, depending
on collector current. On the other hand, transconductance is almost
identical for every transistor at a given collector current, and comes
right out of the simplest version of the device physics (the Ebers-Moll
model).

Monkeys armed with typewriters have mastered basic analog electronics,
so I ought to be able to get there as well. It would be helpful if
there were less disinformation or outright lies in the way, however.
Some people seem strangely committed to making learning as difficult
as possible. I wonder why that is.

They're all conspiring against you.

Only the retard, righttards, and related degenerates and defectives.
Oftentimes they believe (with no evidence) that their mindset is
exclusive to the world's population, but in actual point of fact they
pretend that sensible, rational, normal folk don't exist and only
those with their special brand of prejudice are 'people'. They are
easily identifiable by their myopic insistance that reality must
conform to their view of it, or at least what little of it they
acknowledge.

It's all so tiresome. Greg Egan once wrote of a hypothetical
terrorist group described as "anthrocosmologists" who bear a striking
resemblance to such persons, who impute anthropic principles to
existence a priori -- which is necessarily the opposite to the idea of
undertaking observation to deduce or infer principles of existence.
The sick joke is that this retrograde method of apprehending reality
is called 'knowing' among people of that sort. To 'know' is to bring
an aspect of reality into existence, in contrast to the usual process
of knowledge acquisition normal to scientific pursuit. Losers.

Ohh-kay then. (Smiles, nods, and creeps out the padded cell door,
locking it behind him.)

Are you attempting to say you don't agree with my take on the
righttard way of 'knowing'?

Regards,

Uncle Steve

Nope. We're just saying there's no chance in hell you'll EVER learn
circuit design.

As that great Texas sage Ron White says, "You can't cure stupid.
Stupid is forever."

Congratulations. You have won the discussion without sullying your
argument with the faintest hint of a fact.

It is so helpful when you losers play your cards so quickly, making
the inevitable 'plonk' decision that much simpler. Some of your
marginally more intelligent peers are able to dissemble for days, even
weeks before showing their true colours.

So. Anyone else want to step up and practice your logical and
argumentative fallacies?

Regards,

Uncle Steve

Jim Thompson · Feb 12, 2013

On Tue, 12 Feb 2013 14:34:02 -0500, Uncle Steve <stevet810@gmail.com>
wrote:

On Tue, Feb 12, 2013 at 01:50:32PM +0000, Bob Masta wrote:
On Sun, 10 Feb 2013 09:37:03 -0500, Uncle Steve
stevet810@gmail.com> wrote:

On Sun, Feb 10, 2013 at 01:51:48PM +0000, Bob Masta wrote:
On Sat, 09 Feb 2013 15:38:15 -0500, Uncle Steve
stevet810@gmail.com> wrote:

For educational purposes as well as tweeter break-in, here
is a good compromise solution: Use an op-amp for the front
end of your power amp, and just build the power output
stage. I'd recommend using a "real" op-amp, even a lowly
741, on separate pos and neg supplies. The single-supply
units tend to be much more difficult to apply for decent
audio, and you don't need that kind of distraction just yet.

I may end up doing this, although I am still inclined to see what I
can do with what I have on-hand.

My first post used an OpAmp plus a power stage, just as Bob Masta
proposes.

What did everyone do before op-amps
were available?

Discrete transistor designs... diff-pairs, plus level-shifters to
single-ended for the output stage.

Here is my first OpAmp design... analyzed in detail...

http://www.analog-innovations.com/SED/MC1530-TeachingExercise.pdf

Designed 50 years ago (when I was 22), and still being sold.

Work your way thru the analysis.

[snip]

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice

John Larkin · Feb 12, 2013

On Mon, 11 Feb 2013 14:42:10 -0500, Uncle Steve <stevet810@gmail.com>
wrote:

It's all so tiresome. Greg Egan once wrote of a hypothetical
terrorist group described as "anthrocosmologists" who bear a striking
resemblance to such persons, who impute anthropic principles to
existence a priori -- which is necessarily the opposite to the idea of
undertaking observation to deduce or infer principles of existence.

According to the Copenhagen interpretation, wave functions collapse
into reality when they are observed. Combine that with the
many-universes concept, and I conclude that I have created my own
universe of which you are a minor detail.

--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

Michael A. Terrell · Feb 12, 2013

Jim Thompson wrote:

Uncle Steve wrote:

Uncle Steve

My circuits work. Yours don't. What else can I say?

Stop playing with turds.

Uncle Steve · Feb 12, 2013

On Tue, Feb 12, 2013 at 12:41:49PM -0800, John Larkin wrote:

On Mon, 11 Feb 2013 14:42:10 -0500, Uncle Steve <stevet810@gmail.com
wrote:

It's all so tiresome. Greg Egan once wrote of a hypothetical
terrorist group described as "anthrocosmologists" who bear a striking
resemblance to such persons, who impute anthropic principles to
existence a priori -- which is necessarily the opposite to the idea of
undertaking observation to deduce or infer principles of existence.

According to the Copenhagen interpretation, wave functions collapse
into reality when they are observed. Combine that with the
many-universes concept, and I conclude that I have created my own
universe of which you are a minor detail.

Oh yeah? I have a doomsday device and I fully intend to keep
destroying the universe until I get you. So there.

(p.s. please don't tell the DHS. Thx.)

Regards,

Uncle Steve

--
More than a century has passed since science laid down sound
propositions as to the origins of the universe, but how many have
mastered them or possess the really scientific spirit of criticism? A
few thousands at the outside, who are lost in the midst of hundreds of
millions still steeped in prejudices and superstitions worthy of
savages, who are consequently ever ready to serve as puppets for
religious impostors. -- Peter Kropotkin

Fred Abse · Feb 12, 2013

On Tue, 12 Feb 2013 14:34:02 -0500, Uncle Steve wrote:

What did everyone do before op-amps were
available?

The math...

--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)

Signal amplifier works

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