Transistor circuits, book, devices, etc

[Michael Black]

On Sun, 12 Feb 2017, asdf wrote:

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that
I can buy in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of
what I found in the books.
A transistor is a transistor, you will find dozens that can be
put in place of the one you can't source locally, just with
different names.
As an example, by trial and error I found that the venerable
BC378 made a really good RF PA for battery operated QRP CB
transmitters back in the day, and afaict there's not a single
book or schematic on the Net showing it used as such.

But once you got not that far from the earliest days of transistors, the
upper frequency limit went fairly high for even cheap transistors, so for
low power devices, there wasn't much reason to get something special for
RF. There was a period when the 2N706 was pretty common, and it was used
in everything. Then it shifted, so things like the 2N3904 and the 2N2222
took over, the latter if you needed more current.

Some amateur radio clubs have contests where people build something based
on one type of transistor, and so long as you start with a decent enough
one (but still cheap), you can live with the same device through the whole
equipment.

In the old days, even starting with the CK722, some transistors were
readily available to hobbyists, so they continued to be used. It's not
even clear whether the hobby suppliers picked some transistors or they
reflected what the projects in the magazines used. It was often rare to
go outside a relatively few different types. Every so often someone would
break the mold, so John SImonton at PAIA found some really cheap
transistor that he claimed was good for generating white noise when
reverse biased, so he used a lot of those, once he started buying them.
Some people would use a databook to choose a transistor, but if the picked
something that was hard to get, the readers would complain. So they
reinforced the types that were already used, choosing what was commonly
available. There were exceptions, except even then the device would often
become readily available.

So the 40673 dual gate MOSFET was common in hobby projects where such a
device was required, but you could look and find cheaper MOSFETs, if you
had access to a parts distributor.

Sometimes a part was exotic, but then the author might arrange to buy a
bunch and sell them at cost, or talk some hobby distributor into carrying
them. SOme early microwave transistors were available because someone
working there was a ham so they'd do the work to get the transistor to
someone needing one for a UHF preamp or something.

Michael

 

[Ralph Mowery]

In article <o7qi0r$17l0$1@gioia.aioe.org>, asdf@nospam.com says...

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that
I can buy in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of
what I found in the books.
A transistor is a transistor, you will find dozens that can be
put in place of the one you can't source locally, just with
different names.
As an example, by trial and error I found that the venerable
BC378 made a really good RF PA for battery operated QRP CB
transmitters back in the day, and afaict there's not a single
book or schematic on the Net showing it used as such.

I have found that in many noncritical circuits most any transisitor that
has ratings near the origional will work, especially if a component or
two is changed. Most of the critical components are the resistors and
capacitors and the transistor is just stuck in.

The only way I thought of transistors is like the Obama care law. You
make the transistor and then see what it is or what it does. Never
could see how there could be so many types to do the same thing.

Far different than most of the old vacuum tubes where there are only a
few types ir numbers that did the same function.

 

[Ralph Mowery]

In article <alpine.LNX.2.02.1702121627470.6266@darkstar.example.org>,
et472@ncf.ca says...

Sometimes a part was exotic, but then the author might arrange to buy a
bunch and sell them at cost, or talk some hobby distributor into carrying
them. SOme early microwave transistors were available because someone
working there was a ham so they'd do the work to get the transistor to
someone needing one for a UHF preamp or something.

Michael

Often if a batch or even a large quanity of expensive transistors did
not meet the specs, but were very good compaired what was on the market,
the culls were sold at a low price or given to hams and others.

I remember two things in the eairly computer era. One was the 486
processor that had a bad math coprocessor in it. As that part was not
used in lots of applications, the chips were remarked and sold. Some of
the memory chips, don't recall how big, were half bad. That is they
were made with say an A and B side. They were remarked and sold at a
lower price as they only had half the memory.

 

[Michael Black]

On Sun, 12 Feb 2017, Ralph Mowery wrote:

In article <alpine.LNX.2.02.1702121627470.6266@darkstar.example.org>,
et472@ncf.ca says...


Sometimes a part was exotic, but then the author might arrange to buy a
bunch and sell them at cost, or talk some hobby distributor into carrying
them. SOme early microwave transistors were available because someone
working there was a ham so they'd do the work to get the transistor to
someone needing one for a UHF preamp or something.

Michael


Often if a batch or even a large quanity of expensive transistors did
not meet the specs, but were very good compaired what was on the market,
the culls were sold at a low price or given to hams and others.

I remember two things in the eairly computer era. One was the 486
processor that had a bad math coprocessor in it. As that part was not
used in lots of applications, the chips were remarked and sold. Some of
the memory chips, don't recall how big, were half bad. That is they
were made with say an A and B side. They were remarked and sold at a
lower price as they only had half the memory.

I gather the CK722, supposedly the first transistor available to the
hobbyist, came about that way. They weren't "good enough" so they got
another part number and sold to hobbyists, who where just eager to try out
transistors.

I rmemeber about the RAM, I read about Motorola and it was early 64K. The
yeild was low, so it was worth the effort to sell it as 32K. And then the
yield improved, but companies were still using it, so they sold the
perfect chips under that 32K part number. At some point, the word was
out, if you have this RAM, wire up this pin, you may have 64K. And people
found they did.

So yes, if they can sell a lesser device, it keeps costs down, but with
time the devices may be better than they are spec'd for.

Michael

 

[Michael Black]

On Sun, 12 Feb 2017, Ralph Mowery wrote:

In article <o7qi0r$17l0$1@gioia.aioe.org>, asdf@nospam.com says...

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that
I can buy in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of
what I found in the books.
A transistor is a transistor, you will find dozens that can be
put in place of the one you can't source locally, just with
different names.
As an example, by trial and error I found that the venerable
BC378 made a really good RF PA for battery operated QRP CB
transmitters back in the day, and afaict there's not a single
book or schematic on the Net showing it used as such.

I have found that in many noncritical circuits most any transisitor that
has ratings near the origional will work, especially if a component or
two is changed. Most of the critical components are the resistors and
capacitors and the transistor is just stuck in.

The first few projects I tried to make all failed. I'd go to the parts
store with the list of parts taken from the magazine article, and they'd
provide substutes and whatever, and the projects didn't work. Lots of
reasons, my early lack of soldering skill, maybe the subs were wrong,
maybe the pinout changed so I wired things in wrong. I was just starting,
so I didn't know enough to troubleshoot, or adjust to different
components.

And then when things were working, I was pulling components off circuit
boards. I'd gained enough ground so I could make substitutes, and they
did work.

The only way I thought of transistors is like the Obama care law. You
make the transistor and then see what it is or what it does. Never
could see how there could be so many types to do the same thing.

I suppose a lot of it is if they can sell a whole whopping lot of a
transistor, then if a company wants a certain spec, they might as well
make something that fits the spec, then offer it to anyone else.

Far different than most of the old vacuum tubes where there are only a
few types ir numbers that did the same function.

Of course, there were the oddball tubes that used 35 or 50volts on the
filament, for AC/DC radios, useful for that purpose, but a liability if
you got stuck with a bunch of them since you then needed a much higher
filament voltage. Some things sold enough so they could be very specific,
something like the 6AR8 beam deflection tube intended for color tv sets (I
think I have the number right) but if you could buy them over the counter,
a cheap way to build a balanced mixer, and cheaper than the 7360 that was
in vogue for a while.

ICs the same thing. In the early days, lots of very interesting things,
but with time it was a surprise that some lasted. The 555 found enough
use, while the LM3909 LED flasher was launched with a bunch of
applications, but never saw much use, so it was a surprise it lasted for a
few decades. Some get lost along the way, lots of ICs that were intended
for non-commercial radio work were really neat, but never saw much use,
and disappeared, while ICs for consumer AM/FM radios had longer life,
except someone was always adding a new one that was different but did the
same thing. Then even later, lots of those non-consumer radio ICs were
wiped out when radios started converting to digital to process the
signals.

Michael

 

[asdf]

On Sun, 12 Feb 2017 21:03:42 +0000, Benderthe.evilrobot wrote:

An RF PA with a low power audio transistor? - sounds like
fun....................

That's why I mentioned QRP, that was probably within 200mW or so,
but more than enough for my experiments...
About the frequency, many low power transistors not intended for RF
have an unexpectedly high cutoff frequency. Among my favorites were
the BC238B and BC308B. Well... actually I got a uber cheap lifetime
supply in the nineties from a shop closing the business so I
wanted to see where I could use them and ended up putting them
nearly everywhere I could, including local oscillators up to the
low VHF and audio PA as complementary pair. One could build a
complete multiband superhet by using just these two transistors.

 

[asdf]

On Sun, 12 Feb 2017 14:11:43 -0700, Jim Thompson wrote:

I did it the other way round... used Motorola RF power transistors in my
first non-class-A audio power amplifier (circa 1964).

This reminds me of a bag of old AU-something (IIRC AU108 and some AU111)
germanium power transistors I have somewhere, got like for one Euro.
My idea was to use acouple to build either a Class A headphones amp, or
something to saturate an audio transformer just to see how it sounds
with a guitar connected to it (a clipping DI box).

 

[Tim Wescott]

On Mon, 13 Feb 2017 12:42:09 +0000, asdf wrote:

On Sun, 12 Feb 2017 21:03:42 +0000, Benderthe.evilrobot wrote:

An RF PA with a low power audio transistor? - sounds like
fun....................

That's why I mentioned QRP, that was probably within 200mW or so, but
more than enough for my experiments...
About the frequency, many low power transistors not intended for RF have
an unexpectedly high cutoff frequency. Among my favorites were the
BC238B and BC308B. Well... actually I got a uber cheap lifetime supply
in the nineties from a shop closing the business so I wanted to see
where I could use them and ended up putting them nearly everywhere I
could, including local oscillators up to the low VHF and audio PA as
complementary pair. One could build a complete multiband superhet by
using just these two transistors.

I don't know if it's still done, but there used to be an annual contest
somewhere (at some Hamfest, maybe?) for building a complete QRP
transceiver with only 2N2222 transistors.

Dunno what all the criteria for winning were, but "fewest active devices"
was certainly a bragging point.

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

 

[Benderthe.evilrobot]

"asdf" <asdf@nospam.com> wrote in message
news7sa5v$2gc$1@gioia.aioe.org...

On Sun, 12 Feb 2017 14:11:43 -0700, Jim Thompson wrote:

I did it the other way round... used Motorola RF power transistors in my
first non-class-A audio power amplifier (circa 1964).

This reminds me of a bag of old AU-something (IIRC AU108 and some AU111)
germanium power transistors I have somewhere, got like for one Euro.
My idea was to use acouple to build either a Class A headphones amp, or
something to saturate an audio transformer just to see how it sounds
with a guitar connected to it (a clipping DI box).

They sound like high voltage horizontal transistors - the silicon ones that
came along after, typically had a gain figure between 2 & 8.

 

[Tim Wescott]

On Mon, 13 Feb 2017 11:13:29 -0600, Tim Wescott wrote:

On Mon, 13 Feb 2017 12:42:09 +0000, asdf wrote:

On Sun, 12 Feb 2017 21:03:42 +0000, Benderthe.evilrobot wrote:

An RF PA with a low power audio transistor? - sounds like
fun....................

That's why I mentioned QRP, that was probably within 200mW or so, but
more than enough for my experiments...
About the frequency, many low power transistors not intended for RF
have an unexpectedly high cutoff frequency. Among my favorites were the
BC238B and BC308B. Well... actually I got a uber cheap lifetime supply
in the nineties from a shop closing the business so I wanted to see
where I could use them and ended up putting them nearly everywhere I
could, including local oscillators up to the low VHF and audio PA as
complementary pair. One could build a complete multiband superhet by
using just these two transistors.

I don't know if it's still done, but there used to be an annual contest
somewhere (at some Hamfest, maybe?) for building a complete QRP
transceiver with only 2N2222 transistors.

Dunno what all the criteria for winning were, but "fewest active
devices"
was certainly a bragging point.

Here's the story: http://www.k8iqy.com/qrprigs/2n240/2n240page.html

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

 

[Benderthe.evilrobot]

"Tim Wescott" <tim@seemywebsite.com> wrote in message
news:Q-ydnSVsHLqkdDzFnZ2dnUU7-dWdnZ2d@giganews.com...

On Mon, 13 Feb 2017 12:42:09 +0000, asdf wrote:

On Sun, 12 Feb 2017 21:03:42 +0000, Benderthe.evilrobot wrote:

An RF PA with a low power audio transistor? - sounds like
fun....................

That's why I mentioned QRP, that was probably within 200mW or so, but
more than enough for my experiments...
About the frequency, many low power transistors not intended for RF have
an unexpectedly high cutoff frequency. Among my favorites were the
BC238B and BC308B. Well... actually I got a uber cheap lifetime supply
in the nineties from a shop closing the business so I wanted to see
where I could use them and ended up putting them nearly everywhere I
could, including local oscillators up to the low VHF and audio PA as
complementary pair. One could build a complete multiband superhet by
using just these two transistors.

I don't know if it's still done, but there used to be an annual contest
somewhere (at some Hamfest, maybe?) for building a complete QRP
transceiver with only 2N2222 transistors.

Ham radio more or less extends on from MW (some countries have a marine band
on that border). CB is at least 27MHz - I think the US has a CB band
somewhere around 50MHz.

You can make a QRP rig with BC107s if you don't expect too much in the way
of frequency.

 

[John Larkin]

On Fri, 10 Feb 2017 14:15:58 -0600, Tim Wescott
<seemywebsite@myfooter.really> wrote:

On Fri, 10 Feb 2017 14:14:44 -0600, Tim Wescott wrote:

On Thu, 09 Feb 2017 20:57:50 -0800, John Larkin wrote:

On Wed, 08 Feb 2017 17:58:30 -0600, Tim Wescott
seemywebsite@myfooter.really> wrote:

On Wed, 08 Feb 2017 12:56:05 -0800, John Larkin wrote:

The plastic breadboards are iccky. It's more fun to solder stuff up.

The plastic breadboards are dead reliable, as long as you treat them
right and don't ask more of them than they can provide.

For experimenting with low power stuff at audio frequencies they're
just fine. For high power stuff, anything above 100kHz or so, or
anything that needs to be really precise you'll be spending more effort
fighting the breadboard than learning -- so, solder stuff up.

Come to think of it, I think everything John does comes under at least
one of those three categories of "don't do this on a breadboard", so I
guess he's provisionally allowed to consider them icky.

Another nice thing about soldering a circuit on a slab of FR4 is that
you can label it and keep it for future reference.

True. That doesn't work for me unless it goes into a customer-specific
box (and gawd, but my office is getting overrun with customer-specific
boxes these days!) -- but yes, and a better-organized person that I
might do better.

Actually, I usually end up prototyping circuits with short-run boards --
and it's those that end up in the customer-specific box.

We do that too, but it takes a lot of work and time to lay out a board
and buy it. I can grab my Dremel and have a simple circuit running in
half an hour. That's best for truly one-offs, like evaluating one
component.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[John Larkin]

On 9 Feb 2017 05:46:47 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-02-07, Peter Percival <peterxpercival@hotmail.com> wrote:
I though I'd like to learn a bit about electronics and to that end I'd
like to buy a book of transistor circuits, a breadboard, and various
components to experiment. Can anyone recommend a book that uses
transistors that I can buy in the UK? Also, who is a good supplier of
components generally?

Farnell has a very good reputation but they required me to supply a
company name to open a cash account here (NZ). I'm not sure how they
play in the UK, but I know they are big there.

When I didn't have a company, I invented names to get mags and data
sheets and samples and things. Simple Systems Inc was one.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[John Larkin]

On Sun, 12 Feb 2017 16:37:42 -0500, Michael Black <et472@ncf.ca>
wrote:

On Sun, 12 Feb 2017, asdf wrote:

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that
I can buy in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of
what I found in the books.
A transistor is a transistor, you will find dozens that can be
put in place of the one you can't source locally, just with
different names.
As an example, by trial and error I found that the venerable
BC378 made a really good RF PA for battery operated QRP CB
transmitters back in the day, and afaict there's not a single
book or schematic on the Net showing it used as such.

But once you got not that far from the earliest days of transistors, the
upper frequency limit went fairly high for even cheap transistors, so for
low power devices, there wasn't much reason to get something special for
RF. There was a period when the 2N706 was pretty common, and it was used
in everything. Then it shifted, so things like the 2N3904 and the 2N2222
took over, the latter if you needed more current.

Some amateur radio clubs have contests where people build something based
on one type of transistor, and so long as you start with a decent enough
one (but still cheap), you can live with the same device through the whole
equipment.

In the old days, even starting with the CK722, some transistors were
readily available to hobbyists, so they continued to be used. It's not
even clear whether the hobby suppliers picked some transistors or they
reflected what the projects in the magazines used. It was often rare to
go outside a relatively few different types. Every so often someone would
break the mold, so John SImonton at PAIA found some really cheap
transistor that he claimed was good for generating white noise when
reverse biased, so he used a lot of those, once he started buying them.
Some people would use a databook to choose a transistor, but if the picked
something that was hard to get, the readers would complain. So they
reinforced the types that were already used, choosing what was commonly
available. There were exceptions, except even then the device would often
become readily available.

So the 40673 dual gate MOSFET was common in hobby projects where such a
device was required, but you could look and find cheaper MOSFETs, if you
had access to a parts distributor.

Sometimes a part was exotic, but then the author might arrange to buy a
bunch and sell them at cost, or talk some hobby distributor into carrying
them. SOme early microwave transistors were available because someone
working there was a ham so they'd do the work to get the transistor to
someone needing one for a UHF preamp or something.

Michael

I wonder if anyone sells a lab-starter kit of parts: resistors, caps,
transistors, fets, LEDs, diodes, inductors. Maybe solder, solder wick,
some bits of FR4, even a few tools? DVM? Oscilloscope? Power supply?

You can buy resistor assortments and such from Mouser.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[John Larkin]

On Sun, 12 Feb 2017 20:57:09 -0500, Michael Black <et472@ncf.ca>
wrote:

On Sun, 12 Feb 2017, Ralph Mowery wrote:

In article <alpine.LNX.2.02.1702121627470.6266@darkstar.example.org>,
et472@ncf.ca says...


Sometimes a part was exotic, but then the author might arrange to buy a
bunch and sell them at cost, or talk some hobby distributor into carrying
them. SOme early microwave transistors were available because someone
working there was a ham so they'd do the work to get the transistor to
someone needing one for a UHF preamp or something.

Michael


Often if a batch or even a large quanity of expensive transistors did
not meet the specs, but were very good compaired what was on the market,
the culls were sold at a low price or given to hams and others.

I remember two things in the eairly computer era. One was the 486
processor that had a bad math coprocessor in it. As that part was not
used in lots of applications, the chips were remarked and sold. Some of
the memory chips, don't recall how big, were half bad. That is they
were made with say an A and B side. They were remarked and sold at a
lower price as they only had half the memory.



I gather the CK722, supposedly the first transistor available to the
hobbyist, came about that way. They weren't "good enough" so they got
another part number and sold to hobbyists, who where just eager to try out
transistors.

I rmemeber about the RAM, I read about Motorola and it was early 64K. The
yeild was low, so it was worth the effort to sell it as 32K. And then the
yield improved, but companies were still using it, so they sold the
perfect chips under that 32K part number. At some point, the word was
out, if you have this RAM, wire up this pin, you may have 64K. And people
found they did.

So yes, if they can sell a lesser device, it keeps costs down, but with
time the devices may be better than they are spec'd for.

Some of the Altera FPGAs that are presumably different sizes, and
different prices, are in fact identical.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[John Larkin]

On Sun, 12 Feb 2017 16:38:55 -0500, Ralph Mowery
<rmowery28146@earthlink.net> wrote:

In article <o7qi0r$17l0$1@gioia.aioe.org>, asdf@nospam.com says...

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that
I can buy in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of
what I found in the books.
A transistor is a transistor, you will find dozens that can be
put in place of the one you can't source locally, just with
different names.
As an example, by trial and error I found that the venerable
BC378 made a really good RF PA for battery operated QRP CB
transmitters back in the day, and afaict there's not a single
book or schematic on the Net showing it used as such.

I have found that in many noncritical circuits most any transisitor that
has ratings near the origional will work, especially if a component or
two is changed. Most of the critical components are the resistors and
capacitors and the transistor is just stuck in.

The only way I thought of transistors is like the Obama care law. You
make the transistor and then see what it is or what it does. Never
could see how there could be so many types to do the same thing.

Far different than most of the old vacuum tubes where there are only a
few types ir numbers that did the same function.

The 2N series seems to be up to 2N7640. Then there the BCXs and 2SKs
and all that.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[George Herold]

On Monday, February 13, 2017 at 8:59:23 PM UTC-5, John Larkin wrote:

On Sun, 12 Feb 2017 16:37:42 -0500, Michael Black <et472@ncf.ca
wrote:

On Sun, 12 Feb 2017, asdf wrote:

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that
I can buy in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of
what I found in the books.
A transistor is a transistor, you will find dozens that can be
put in place of the one you can't source locally, just with
different names.
As an example, by trial and error I found that the venerable
BC378 made a really good RF PA for battery operated QRP CB
transmitters back in the day, and afaict there's not a single
book or schematic on the Net showing it used as such.

But once you got not that far from the earliest days of transistors, the
upper frequency limit went fairly high for even cheap transistors, so for
low power devices, there wasn't much reason to get something special for
RF. There was a period when the 2N706 was pretty common, and it was used
in everything. Then it shifted, so things like the 2N3904 and the 2N2222
took over, the latter if you needed more current.

Some amateur radio clubs have contests where people build something based
on one type of transistor, and so long as you start with a decent enough
one (but still cheap), you can live with the same device through the whole
equipment.

In the old days, even starting with the CK722, some transistors were
readily available to hobbyists, so they continued to be used. It's not
even clear whether the hobby suppliers picked some transistors or they
reflected what the projects in the magazines used. It was often rare to
go outside a relatively few different types. Every so often someone would
break the mold, so John SImonton at PAIA found some really cheap
transistor that he claimed was good for generating white noise when
reverse biased, so he used a lot of those, once he started buying them.
Some people would use a databook to choose a transistor, but if the picked
something that was hard to get, the readers would complain. So they
reinforced the types that were already used, choosing what was commonly
available. There were exceptions, except even then the device would often
become readily available.

So the 40673 dual gate MOSFET was common in hobby projects where such a
device was required, but you could look and find cheaper MOSFETs, if you
had access to a parts distributor.

Sometimes a part was exotic, but then the author might arrange to buy a
bunch and sell them at cost, or talk some hobby distributor into carrying
them. SOme early microwave transistors were available because someone
working there was a ham so they'd do the work to get the transistor to
someone needing one for a UHF preamp or something.

Michael

I wonder if anyone sells a lab-starter kit of parts: resistors, caps,
transistors, fets, LEDs, diodes, inductors. Maybe solder, solder wick,
some bits of FR4, even a few tools? DVM? Oscilloscope? Power supply?

I haven't really spent much time on their websites, but
adafruit and sparkfun are kinda filling that niche. I guess there are
a lot of adruinos involved. But I figure adruino is a good "gate way"
drug for electronics these days.

George H.

You can buy resistor assortments and such from Mouser.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Tim Wescott]

On Tue, 14 Feb 2017 06:49:43 -0800, George Herold wrote:

On Monday, February 13, 2017 at 8:59:23 PM UTC-5, John Larkin wrote:
On Sun, 12 Feb 2017 16:37:42 -0500, Michael Black <et472@ncf.ca> wrote:

On Sun, 12 Feb 2017, asdf wrote:

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that I can
buy in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of what I
found in the books.
A transistor is a transistor, you will find dozens that can be put
in place of the one you can't source locally, just with different
names.
As an example, by trial and error I found that the venerable BC378
made a really good RF PA for battery operated QRP CB transmitters
back in the day, and afaict there's not a single book or schematic
on the Net showing it used as such.

But once you got not that far from the earliest days of transistors,
the upper frequency limit went fairly high for even cheap transistors,
so for low power devices, there wasn't much reason to get something
special for RF. There was a period when the 2N706 was pretty common,
and it was used in everything. Then it shifted, so things like the
2N3904 and the 2N2222 took over, the latter if you needed more
current.

Some amateur radio clubs have contests where people build something
based on one type of transistor, and so long as you start with a
decent enough one (but still cheap), you can live with the same device
through the whole equipment.

In the old days, even starting with the CK722, some transistors were
readily available to hobbyists, so they continued to be used. It's
not even clear whether the hobby suppliers picked some transistors or
they reflected what the projects in the magazines used. It was often
rare to go outside a relatively few different types. Every so often
someone would break the mold, so John SImonton at PAIA found some
really cheap transistor that he claimed was good for generating white
noise when reverse biased, so he used a lot of those, once he started
buying them. Some people would use a databook to choose a transistor,
but if the picked something that was hard to get, the readers would
complain. So they reinforced the types that were already used,
choosing what was commonly available. There were exceptions, except
even then the device would often become readily available.

So the 40673 dual gate MOSFET was common in hobby projects where such
a device was required, but you could look and find cheaper MOSFETs, if
you had access to a parts distributor.

Sometimes a part was exotic, but then the author might arrange to buy
a bunch and sell them at cost, or talk some hobby distributor into
carrying them. SOme early microwave transistors were available
because someone working there was a ham so they'd do the work to get
the transistor to someone needing one for a UHF preamp or something.

Michael

I wonder if anyone sells a lab-starter kit of parts: resistors, caps,
transistors, fets, LEDs, diodes, inductors. Maybe solder, solder wick,
some bits of FR4, even a few tools? DVM? Oscilloscope? Power supply?

I haven't really spent much time on their websites, but adafruit and
sparkfun are kinda filling that niche. I guess there are a lot of
adruinos involved. But I figure adruino is a good "gate way" drug for
electronics these days.

I have a friend who's an ex-machinist who would have _never_ been able to
build a 'puter board from scratch but who's done an Arduino project.
He's gone off to other things because he has the attention span of a
flea, but he sat down, did the deed, and then wandered off to other
things.

So, yes, and it does so admirably.

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

 

[Tim Wescott]

On Mon, 13 Feb 2017 17:59:16 -0800, John Larkin wrote:

On Sun, 12 Feb 2017 16:37:42 -0500, Michael Black <et472@ncf.ca> wrote:

On Sun, 12 Feb 2017, asdf wrote:

On Tue, 07 Feb 2017 21:50:20 +0000, Peter Percival wrote:

... Can anyone recommend a book that uses transistors that I can buy
in the UK? ...

Don't let an obscure component label stop you from adapting the
schematic; I learned a lot by using functional equivalents of what I
found in the books.
A transistor is a transistor, you will find dozens that can be put in
place of the one you can't source locally, just with different names.
As an example, by trial and error I found that the venerable BC378
made a really good RF PA for battery operated QRP CB transmitters back
in the day, and afaict there's not a single book or schematic on the
Net showing it used as such.

But once you got not that far from the earliest days of transistors, the
upper frequency limit went fairly high for even cheap transistors, so
for low power devices, there wasn't much reason to get something special
for RF. There was a period when the 2N706 was pretty common, and it was
used in everything. Then it shifted, so things like the 2N3904 and the
2N2222 took over, the latter if you needed more current.

Some amateur radio clubs have contests where people build something
based on one type of transistor, and so long as you start with a decent
enough one (but still cheap), you can live with the same device through
the whole equipment.

In the old days, even starting with the CK722, some transistors were
readily available to hobbyists, so they continued to be used. It's not
even clear whether the hobby suppliers picked some transistors or they
reflected what the projects in the magazines used. It was often rare to
go outside a relatively few different types. Every so often someone
would break the mold, so John SImonton at PAIA found some really cheap
transistor that he claimed was good for generating white noise when
reverse biased, so he used a lot of those, once he started buying them.
Some people would use a databook to choose a transistor, but if the
picked something that was hard to get, the readers would complain. So
they reinforced the types that were already used, choosing what was
commonly available. There were exceptions, except even then the device
would often become readily available.

So the 40673 dual gate MOSFET was common in hobby projects where such a
device was required, but you could look and find cheaper MOSFETs, if you
had access to a parts distributor.

Sometimes a part was exotic, but then the author might arrange to buy a
bunch and sell them at cost, or talk some hobby distributor into
carrying them. SOme early microwave transistors were available because
someone working there was a ham so they'd do the work to get the
transistor to someone needing one for a UHF preamp or something.

Michael

I wonder if anyone sells a lab-starter kit of parts: resistors, caps,
transistors, fets, LEDs, diodes, inductors. Maybe solder, solder wick,
some bits of FR4, even a few tools? DVM? Oscilloscope? Power supply?

You can buy resistor assortments and such from Mouser.

I think most labs start these days with an Arduino and a shield -- most
of the fun component-level projects are already done, built, and for
sale, and much of the "DIY" activity is happening more at the system
level.

Which may be strange and painful to see for us old folk, but hey -- if
it's getting the job done for people, who are we to complain?

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

 

[Michael A. Terrell]

Phil Hobbs wrote:

The usual problems people have with learning to solder are:

1. Dirty tips. Use a wet cellulose sponge or some brass wool every
time you pick up the iron.

DAMP, not WET! If the tip cools unevenly, you will cause
micro-fractures in the iron plating, causing premature tip failure.


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)