Newbie question: EMDR project

On Tue, 24 May 2011, Rich Grise wrote:

krw@att.bizzzzzzzzzzzz wrote:
On Mon, 23 May 2011 20:55:29 -0700, Rich Grise <richg@example.net.invalid

I think one of the gurun around here presented it a couple of years ago.
:)

Maybe, but I don't see it. Then again, I've never managed to design one
into
a circuit. The projects were either cancelled or I found a better way.
;-)

IIRC, whoever it was just fed the output (probably a CMOS 555 would work
better) back to both the threshold and trigger, or something like that,
essentially reducing the 555 to an inverter in one of those inverter
oscillator arrangements.

With my luck, it was John Woodgate or somebody like that. I wonder
if Spehro or either of the other Johns are following the thread; I'm
almost sure it was one of those guys, or that other guy whose name
I can't remember - it was some years ago.

The idea predates these newsgroups.
Click to expand...

I saw it in "Electronics" in something like the Designer's Notebook (or
the other similar feature, Something Casebook)). It even predates the
CMOS 555.

It must have been around 1974. I took the circuit, left off the pullup
resistor that didn't matter to me, and every time since I needed a simple
square wave oscillator, I've used that. It beats fussing with two
timing resistors like the standard 555 circuit requires. Yes, in some
cases you want something fancier, but for a lot of uses, it doesn't
matter.

The circuit has been in Walter Jung's "IC Timer Cookbook" since 1977.
It references the original article, which was in "Electronics" for June
21st, 1973, S.A. Orrel wrote the bit, "IC Timer Plus Resistor Can Produce
Square Waves". So obviously there was no pullup in the original, the
circuit in the book doesn't show one and that blurb indicates otherwise.

Walter Jung then shows an improved circuit, that has a 1K pullup resistor
from pin 3 of the 555 to the positive supply, to get rid of the
assymetrical output. He doesn't credit anyone for that circuit, so he may
be the originator.


Pin 3, the output of the 555, goes through a timing resistor to where pins
6 and 2 are connected in parallel, with a timing capacitor from that
junction to ground.

Michael
 
On Sat, 21 May 2011 08:34:26 -0700, Snit
<usenet@gallopinginsanity.com> wrote:

No idea how to proceed with making what is likely a pretty simple device,
but I have *no* background in electronics. OK, here is what I want:

Two handheld cell-phone style vibrators that "take turns" vibrating, each
connected to a central control device which allows changing the speed of the
switching back and forth.

As a bonus, but not needed, it would be good to have a way to connect
headphones which would be able to play some sound that is timed to the same
back-and-forth behavior: when the left "vibrator" (is there a better word!)
is active, a sound is played for the left ear; same thing for the right.

I suspect for someone who has a clue this is not that hard to make... but
for me: completely out of my league. Any ideas? Wrong group?
Click to expand...
---
View with a fixed-pitch font:


.. +-------------------->AUDIO L
.. |
.. +----[7k5]----+ +----[7k5]----+--->AUDIO R
.. | +-------+ | | +-------+ |
.. +--|TH OUT|--+ +--|TH OUT|--+ +V +V +V +V
.. | |___ _| | | _| | |K | |K
.. +-O|DIS R|O-+ +-O|DIS R|O-+ [VIBR][CR] [VIBL][CR]
.. | +-------+ | | +-------+ | | | | |
..[0ľ1] 7555 U1 |[0ľ1] 7555 U2 | +-+-+ +-+-+
.. | | | | | |
.. GND | GND | C C
.. +---+ +-[1k]-B NPN +-[1k]-B NPN
.. | | E | E
.. +--[1M POT]--+ | | | | |
.. | | +---------+ | GND | GND
.. [68k] | | +----+ | | |
.. | +-------+ | +-|D Q|--|--+ |
.. +--|TH OUT|-+-----|> _| | |
.. | |___ _| | Q|O-+----------------+
.. +-O|DIS R|O-Vcc +----+
.. | +-------+ HC74 U4
.. |+ 7555 U3
.. [1ľ0]
.. |
.. GND

U1 and U2 are set to oscillate at about 1kHz.

U3 has a period of about 100ms with the pot set to minimum R, and
about 1.4 seconds with the pot at max R, so the outputs of U4 will
toggle at those rates.

Power pins aren't shown, and the diodes are anything that can handle
the discharge current from the motors; 1N4148 most likely, 1N40XX for
sure.

--
JF
 
On Tue, 24 May 2011 12:53:23 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sat, 21 May 2011 08:34:26 -0700, Snit
usenet@gallopinginsanity.com> wrote:

No idea how to proceed with making what is likely a pretty simple device,
but I have *no* background in electronics. OK, here is what I want:

Two handheld cell-phone style vibrators that "take turns" vibrating, each
connected to a central control device which allows changing the speed of the
switching back and forth.

As a bonus, but not needed, it would be good to have a way to connect
headphones which would be able to play some sound that is timed to the same
back-and-forth behavior: when the left "vibrator" (is there a better word!)
is active, a sound is played for the left ear; same thing for the right.

I suspect for someone who has a clue this is not that hard to make... but
for me: completely out of my league. Any ideas? Wrong group?

---
View with a fixed-pitch font:


. +-------------------->AUDIO L
. |
. +----[7k5]----+ +----[7k5]----+--->AUDIO R
. | +-------+ | | +-------+ |
. +--|TH OUT|--+ +--|TH OUT|--+ +V +V +V +V
. | |___ _| | | _| | |K | |K
. +-O|DIS R|O-+ +-O|DIS R|O-+ [VIBR][CR] [VIBL][CR]
. | +-------+ | | +-------+ | | | | |
.[0ľ1] 7555 U1 |[0ľ1] 7555 U2 | +-+-+ +-+-+
. | | | | | |
. GND | GND | C C
. +---+ +-[1k]-B NPN +-[1k]-B NPN
. | | E | E
. +--[1M POT]--+ | | | | |
. | | +---------+ | GND | GND
. [68k] | | +----+ | | |
. | +-------+ | +-|D Q|--|--+ |
. +--|TH OUT|-+-----|> _| | |
. | |___ _| | Q|O-+----------------+
. +-O|DIS R|O-Vcc +----+
. | +-------+ HC74 U4
. |+ 7555 U3
. [1ľ0]
. |
. GND

U1 and U2 are set to oscillate at about 1kHz.

U3 has a period of about 100ms with the pot set to minimum R, and
about 1.4 seconds with the pot at max R, so the outputs of U4 will
toggle at those rates.

Power pins aren't shown, and the diodes are anything that can handle
the discharge current from the motors; 1N4148 most likely, 1N40XX for
sure.
Click to expand...
---
Oops...

It's threshold and trigger in parallel, not threshold and discharge:

.. +-------------------->AUDIO L
.. |
.. +----[7k5]----+ +----[7k5]----+--->AUDIO R
.. | +-------+ | | +-------+ |
.. +--|TH OUT|--+ +--|TH OUT|--+ +V +V +V +V
.. | |__ _| | |__ _| | |K | |K
.. +-O|TR R|O-+ +-O|TR R|O-+ [VIBR][CR] [VIBL][CR]
.. | +-------+ | | +-------+ | | | | |
..[0ľ1] 7555 U1 |[0ľ1] 7555 U2 | +-+-+ +-+-+
.. | | | | | |
.. GND | GND | C C
.. +---+ +-[1k]-B NPN +-[1k]-B NPN
.. | | E | E
.. +--[1M POT]--+ | | | | |
.. | | +---------+ | GND | GND
.. [68k] | | +----+ | | |
.. | +-------+ | +-|D Q|--|--+ |
.. +--|TH OUT|-+-----|> _| | |
.. | |__ _| | Q|O-+----------------+
.. +-O|TR R|O-Vcc +----+
.. | +-------+ HC74 U4
.. |+ 7555 U3
.. [1ľ0]
.. |
.. GND

--
JF
 
Michael Black wrote:
On Tue, 24 May 2011, Rich Grise wrote:

krw@att.bizzzzzzzzzzzz wrote:
On Mon, 23 May 2011 20:55:29 -0700, Rich Grise
richg@example.net.invalid

I think one of the gurun around here presented it a couple of years
ago.
:)

Maybe, but I don't see it. Then again, I've never managed to design one
into
a circuit. The projects were either cancelled or I found a better way.
;-)

IIRC, whoever it was just fed the output (probably a CMOS 555 would work
better) back to both the threshold and trigger, or something like that,
essentially reducing the 555 to an inverter in one of those inverter
oscillator arrangements.

With my luck, it was John Woodgate or somebody like that. I wonder
if Spehro or either of the other Johns are following the thread; I'm
almost sure it was one of those guys, or that other guy whose name
I can't remember - it was some years ago.

The idea predates these newsgroups.

I saw it in "Electronics" in something like the Designer's Notebook (or
the other similar feature, Something Casebook)). It even predates the
CMOS 555.

It must have been around 1974. I took the circuit, left off the pullup
resistor that didn't matter to me, and every time since I needed a
simple square wave oscillator, I've used that. It beats fussing with two
timing resistors like the standard 555 circuit requires. Yes, in some
cases you want something fancier, but for a lot of uses, it doesn't matter.

The circuit has been in Walter Jung's "IC Timer Cookbook" since 1977.
It references the original article, which was in "Electronics" for June
21st, 1973, S.A. Orrel wrote the bit, "IC Timer Plus Resistor Can
Produce Square Waves". So obviously there was no pullup in the original,
the circuit in the book doesn't show one and that blurb indicates
otherwise.

Walter Jung then shows an improved circuit, that has a 1K pullup
resistor from pin 3 of the 555 to the positive supply, to get rid of the
assymetrical output. He doesn't credit anyone for that circuit, so he
may be the originator.


Pin 3, the output of the 555, goes through a timing resistor to where
pins 6 and 2 are connected in parallel, with a timing capacitor from
that junction to ground.

Michael
Click to expand...
It doesn't work well except with CMOS 555s, and then only when the
output is lightly loaded. The logic levels of the bipolar part don't
track the power supply voltage, so the supply rejection goes south.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net
 
On Tue, 24 May 2011 16:51:35 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Michael Black wrote:
On Tue, 24 May 2011, Rich Grise wrote:

krw@att.bizzzzzzzzzzzz wrote:
On Mon, 23 May 2011 20:55:29 -0700, Rich Grise
richg@example.net.invalid

I think one of the gurun around here presented it a couple of years
ago.
:)

Maybe, but I don't see it. Then again, I've never managed to design one
into
a circuit. The projects were either cancelled or I found a better way.
;-)

IIRC, whoever it was just fed the output (probably a CMOS 555 would work
better) back to both the threshold and trigger, or something like that,
essentially reducing the 555 to an inverter in one of those inverter
oscillator arrangements.

With my luck, it was John Woodgate or somebody like that. I wonder
if Spehro or either of the other Johns are following the thread; I'm
almost sure it was one of those guys, or that other guy whose name
I can't remember - it was some years ago.

The idea predates these newsgroups.

I saw it in "Electronics" in something like the Designer's Notebook (or
the other similar feature, Something Casebook)). It even predates the
CMOS 555.

It must have been around 1974. I took the circuit, left off the pullup
resistor that didn't matter to me, and every time since I needed a
simple square wave oscillator, I've used that. It beats fussing with two
timing resistors like the standard 555 circuit requires. Yes, in some
cases you want something fancier, but for a lot of uses, it doesn't matter.

The circuit has been in Walter Jung's "IC Timer Cookbook" since 1977.
It references the original article, which was in "Electronics" for June
21st, 1973, S.A. Orrel wrote the bit, "IC Timer Plus Resistor Can
Produce Square Waves". So obviously there was no pullup in the original,
the circuit in the book doesn't show one and that blurb indicates
otherwise.

Walter Jung then shows an improved circuit, that has a 1K pullup
resistor from pin 3 of the 555 to the positive supply, to get rid of the
assymetrical output. He doesn't credit anyone for that circuit, so he
may be the originator.


Pin 3, the output of the 555, goes through a timing resistor to where
pins 6 and 2 are connected in parallel, with a timing capacitor from
that junction to ground.

Michael


It doesn't work well except with CMOS 555s, and then only when the
output is lightly loaded. The logic levels of the bipolar part don't
track the power supply voltage, so the supply rejection goes south.

Cheers

Phil Hobbs
Click to expand...
---
The problem isn't that the logic levels of the bipolar part don't
track the supply voltage, because they do.

They _have_ to because the references for the threshold and trigger
comparators are generated by a three-resistor voltage divider
connected between Vcc and ground with one of the comparators' inputs
connected to the two junctions.

That way the references are ratiometric and are _always_ 1/3 Vcc and
2/3 Vcc.

The problem is that if the bipolar part is operated at a low voltage,
Vce(sat) of the upper totem-pole emitter follower can fall below
2/3Vcc, making it impossible to switch the front end.

--
JF
 
John Fields wrote:
On Tue, 24 May 2011 16:51:35 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Michael Black wrote:
On Tue, 24 May 2011, Rich Grise wrote:

krw@att.bizzzzzzzzzzzz wrote:
On Mon, 23 May 2011 20:55:29 -0700, Rich Grise
richg@example.net.invalid

I think one of the gurun around here presented it a couple of years
ago.
:)

Maybe, but I don't see it. Then again, I've never managed to design one
into
a circuit. The projects were either cancelled or I found a better way.
;-)

IIRC, whoever it was just fed the output (probably a CMOS 555 would work
better) back to both the threshold and trigger, or something like that,
essentially reducing the 555 to an inverter in one of those inverter
oscillator arrangements.

With my luck, it was John Woodgate or somebody like that. I wonder
if Spehro or either of the other Johns are following the thread; I'm
almost sure it was one of those guys, or that other guy whose name
I can't remember - it was some years ago.

The idea predates these newsgroups.

I saw it in "Electronics" in something like the Designer's Notebook (or
the other similar feature, Something Casebook)). It even predates the
CMOS 555.

It must have been around 1974. I took the circuit, left off the pullup
resistor that didn't matter to me, and every time since I needed a
simple square wave oscillator, I've used that. It beats fussing with two
timing resistors like the standard 555 circuit requires. Yes, in some
cases you want something fancier, but for a lot of uses, it doesn't matter.

The circuit has been in Walter Jung's "IC Timer Cookbook" since 1977.
It references the original article, which was in "Electronics" for June
21st, 1973, S.A. Orrel wrote the bit, "IC Timer Plus Resistor Can
Produce Square Waves". So obviously there was no pullup in the original,
the circuit in the book doesn't show one and that blurb indicates
otherwise.

Walter Jung then shows an improved circuit, that has a 1K pullup
resistor from pin 3 of the 555 to the positive supply, to get rid of the
assymetrical output. He doesn't credit anyone for that circuit, so he
may be the originator.


Pin 3, the output of the 555, goes through a timing resistor to where
pins 6 and 2 are connected in parallel, with a timing capacitor from
that junction to ground.

Michael


It doesn't work well except with CMOS 555s, and then only when the
output is lightly loaded. The logic levels of the bipolar part don't
track the power supply voltage, so the supply rejection goes south.

Cheers

Phil Hobbs

---
The problem isn't that the logic levels of the bipolar part don't
track the supply voltage, because they do.

They _have_ to because the references for the threshold and trigger
comparators are generated by a three-resistor voltage divider
connected between Vcc and ground with one of the comparators' inputs
connected to the two junctions.

That way the references are ratiometric and are _always_ 1/3 Vcc and
2/3 Vcc.

The problem is that if the bipolar part is operated at a low voltage,
Vce(sat) of the upper totem-pole emitter follower can fall below
2/3Vcc, making it impossible to switch the front end.
Click to expand...
_Logic_ levels, not comparator thresholds--the output high and low
levels are not too close to the rails on the bipolar part, which makes
the ratiometric property fail to work.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net
 
On Tue, 24 May 2011 17:50:07 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Fields wrote:
On Tue, 24 May 2011 16:51:35 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

It doesn't work well except with CMOS 555s, and then only when the
output is lightly loaded. The logic levels of the bipolar part don't
track the power supply voltage, so the supply rejection goes south.

Cheers

Phil Hobbs

---
The problem isn't that the logic levels of the bipolar part don't
track the supply voltage, because they do.

They _have_ to because the references for the threshold and trigger
comparators are generated by a three-resistor voltage divider
connected between Vcc and ground with one of the comparators' inputs
connected to the two junctions.

That way the references are ratiometric and are _always_ 1/3 Vcc and
2/3 Vcc.

The problem is that if the bipolar part is operated at a low voltage,
Vce(sat) of the upper totem-pole emitter follower can fall below
2/3Vcc, making it impossible to switch the front end.


_Logic_ levels, not comparator thresholds--the output high and low
levels are not too close to the rails on the bipolar part, which makes
the ratiometric property fail to work.

Cheers

Phil Hobbs
Click to expand...
---
But the output _does_ track the supply in that for any given current
out, the output voltage will vary as the supply does.

It's exactly the same with CMOS but, since the CMOS output is closer
to the rails, it extends the working range of the ratiometric
property.

--
JF
 
John Fields wrote:
On Tue, 24 May 2011 17:50:07 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Fields wrote:
On Tue, 24 May 2011 16:51:35 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

It doesn't work well except with CMOS 555s, and then only when the
output is lightly loaded. The logic levels of the bipolar part don't
track the power supply voltage, so the supply rejection goes south.

Cheers

Phil Hobbs

---
The problem isn't that the logic levels of the bipolar part don't
track the supply voltage, because they do.

They _have_ to because the references for the threshold and trigger
comparators are generated by a three-resistor voltage divider
connected between Vcc and ground with one of the comparators' inputs
connected to the two junctions.

That way the references are ratiometric and are _always_ 1/3 Vcc and
2/3 Vcc.

The problem is that if the bipolar part is operated at a low voltage,
Vce(sat) of the upper totem-pole emitter follower can fall below
2/3Vcc, making it impossible to switch the front end.


_Logic_ levels, not comparator thresholds--the output high and low
levels are not too close to the rails on the bipolar part, which makes
the ratiometric property fail to work.

Cheers

Phil Hobbs

---
But the output _does_ track the supply in that for any given current
out, the output voltage will vary as the supply does.

It's exactly the same with CMOS but, since the CMOS output is closer
to the rails, it extends the working range of the ratiometric
property.
Click to expand...
You're trumping up a silly semantic issue by foisting your definition of
'track' where it doesn't fit. That winds up being nonsense, as you say,
but it's your nonsense and not mine.

If the output high level is, say, two VBEs below the positive supply,
the charging current and the upper comparator threshold won't track each
other as the supply voltage changes. That makes the frequency and duty
cycle supply voltage dependent.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net
 
John Fields stated in post qr4ot6pji0p9piprf2hdvgghriuvk4thja@4ax.com on
5/24/11 1:25 PM:

On Tue, 24 May 2011 12:53:23 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 21 May 2011 08:34:26 -0700, Snit
usenet@gallopinginsanity.com> wrote:

No idea how to proceed with making what is likely a pretty simple device,
but I have *no* background in electronics. OK, here is what I want:

Two handheld cell-phone style vibrators that "take turns" vibrating, each
connected to a central control device which allows changing the speed of the
switching back and forth.

As a bonus, but not needed, it would be good to have a way to connect
headphones which would be able to play some sound that is timed to the same
back-and-forth behavior: when the left "vibrator" (is there a better word!)
is active, a sound is played for the left ear; same thing for the right.

I suspect for someone who has a clue this is not that hard to make... but
for me: completely out of my league. Any ideas? Wrong group?

---
View with a fixed-pitch font:


. +-------------------->AUDIO L
. |
. +----[7k5]----+ +----[7k5]----+--->AUDIO R
. | +-------+ | | +-------+ |
. +--|TH OUT|--+ +--|TH OUT|--+ +V +V +V +V
. | |___ _| | | _| | |K | |K
. +-O|DIS R|O-+ +-O|DIS R|O-+ [VIBR][CR] [VIBL][CR]
. | +-------+ | | +-------+ | | | | |
.[0ľ1] 7555 U1 |[0ľ1] 7555 U2 | +-+-+ +-+-+
. | | | | | |
. GND | GND | C C
. +---+ +-[1k]-B NPN +-[1k]-B NPN
. | | E | E
. +--[1M POT]--+ | | | | |
. | | +---------+ | GND | GND
. [68k] | | +----+ | | |
. | +-------+ | +-|D Q|--|--+ |
. +--|TH OUT|-+-----|> _| | |
. | |___ _| | Q|O-+----------------+
. +-O|DIS R|O-Vcc +----+
. | +-------+ HC74 U4
. |+ 7555 U3
. [1ľ0]
. |
. GND

U1 and U2 are set to oscillate at about 1kHz.

U3 has a period of about 100ms with the pot set to minimum R, and
about 1.4 seconds with the pot at max R, so the outputs of U4 will
toggle at those rates.

Power pins aren't shown, and the diodes are anything that can handle
the discharge current from the motors; 1N4148 most likely, 1N40XX for
sure.

---
Oops...

It's threshold and trigger in parallel, not threshold and discharge:

. +-------------------->AUDIO L

. |

. +----[7k5]----+ +----[7k5]----+--->AUDIO R

. | +-------+ | | +-------+ |

. +--|TH OUT|--+ +--|TH OUT|--+ +V +V +V +V

. | |__ _| | |__ _| | |K | |K

. +-O|TR R|O-+ +-O|TR R|O-+ [VIBR][CR] [VIBL][CR]

. | +-------+ | | +-------+ | | | | |

.[0ľ1] 7555 U1 |[0ľ1] 7555 U2 | +-+-+ +-+-+

. | | | | | |

. GND | GND | C C

. +---+ +-[1k]-B NPN +-[1k]-B NPN

. | | E | E

. +--[1M POT]--+ | | | | |

. | | +---------+ | GND | GND

. [68k] | | +----+ | | |

. | +-------+ | +-|D Q|--|--+ |

. +--|TH OUT|-+-----|> _| | |

. | |__ _| | Q|O-+----------------+

. +-O|TR R|O-Vcc +----+

. | +-------+ HC74 U4

. |+ 7555 U3

. [1ľ0]

. |

. GND

Thanks!
Click to expand...


--
[INSERT .SIG HERE]
 
On Tue, 24 May 2011 18:55:59 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Fields wrote:
On Tue, 24 May 2011 17:50:07 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Fields wrote:
On Tue, 24 May 2011 16:51:35 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

It doesn't work well except with CMOS 555s, and then only when the
output is lightly loaded. The logic levels of the bipolar part don't
track the power supply voltage, so the supply rejection goes south.

Cheers

Phil Hobbs

---
The problem isn't that the logic levels of the bipolar part don't
track the supply voltage, because they do.

They _have_ to because the references for the threshold and trigger
comparators are generated by a three-resistor voltage divider
connected between Vcc and ground with one of the comparators' inputs
connected to the two junctions.

That way the references are ratiometric and are _always_ 1/3 Vcc and
2/3 Vcc.

The problem is that if the bipolar part is operated at a low voltage,
Vce(sat) of the upper totem-pole emitter follower can fall below
2/3Vcc, making it impossible to switch the front end.


_Logic_ levels, not comparator thresholds--the output high and low
levels are not too close to the rails on the bipolar part, which makes
the ratiometric property fail to work.

Cheers

Phil Hobbs

---
But the output _does_ track the supply in that for any given current
out, the output voltage will vary as the supply does.

It's exactly the same with CMOS but, since the CMOS output is closer
to the rails, it extends the working range of the ratiometric
property.


You're trumping up a silly semantic issue by foisting your definition of
'track' where it doesn't fit.
Click to expand...
---
Really?

If the supply voltage changes and the output voltage of the logic
follows the change, how is that not "tracking"?
---

That winds up being nonsense, as you say,
but it's your nonsense and not mine.
Click to expand...
---
Casting unwarranted aspersions so early in the game?

I'm disappointed in you.

I haven't yet pronounced anything here as being nonsensical, so your
attempt at forcing words into my mouth is, at best, disingenuous and
at worst, Larkinesque.
---

If the output high level is, say, two VBEs below the positive supply,
the charging current and the upper comparator threshold won't track each
other as the supply voltage changes. That makes the frequency and duty
cycle supply voltage dependent.
Click to expand...
---
True:

Version 4
SHEET 1 1156 680
WIRE 112 -240 -80 -240
WIRE 384 -240 112 -240
WIRE 704 -240 384 -240
WIRE 1024 -240 704 -240
WIRE 1088 -240 1024 -240
WIRE 112 -192 112 -240
WIRE 384 -192 384 -240
WIRE 1088 -192 1088 -240
WIRE 752 -128 512 -128
WIRE 1024 -128 1024 -240
WIRE 1024 -128 976 -128
WIRE 112 -64 112 -128
WIRE 208 -64 112 -64
WIRE 384 -64 384 -112
WIRE 384 -64 288 -64
WIRE 752 -64 384 -64
WIRE 1088 -64 1088 -112
WIRE 1088 -64 976 -64
WIRE 752 0 592 0
WIRE 1088 0 1088 -64
WIRE 1088 0 976 0
WIRE 112 64 112 -64
WIRE 592 64 592 0
WIRE 704 64 704 -240
WIRE 752 64 704 64
WIRE 1088 96 1088 0
WIRE -80 112 -80 -240
WIRE 224 112 224 -16
WIRE -80 256 -80 192
WIRE 112 256 112 144
WIRE 112 256 -80 256
WIRE 224 256 224 192
WIRE 224 256 112 256
WIRE 272 256 272 -16
WIRE 272 256 224 256
WIRE 512 256 512 -128
WIRE 512 256 272 256
WIRE 592 256 592 144
WIRE 592 256 512 256
WIRE 1088 256 1088 160
WIRE 1088 256 592 256
WIRE -80 336 -80 256
FLAG -80 336 0
SYMBOL Misc\\NE555 864 -32 R0
SYMATTR InstName U1
SYMBOL voltage -80 96 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL voltage 224 96 R0
WINDOW 0 -53 5 Left 0
WINDOW 3 -242 110 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 1 1 1E-6)
SYMBOL sw 304 -64 M270
WINDOW 0 43 40 Left 0
WINDOW 3 40 76 Left 0
SYMATTR InstName S1
SYMBOL res 128 160 R180
WINDOW 0 36 76 Left 0
WINDOW 3 36 40 Left 0
SYMATTR InstName R1
SYMATTR Value 100k
SYMBOL cap 96 -192 R0
SYMATTR InstName C1
SYMATTR Value 1e-7
SYMBOL res 368 -208 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL res 576 48 R0
SYMATTR InstName R3
SYMATTR Value 1000
SYMBOL res 1072 -208 R0
SYMATTR InstName R4
SYMATTR Value 1e6
SYMBOL cap 1072 96 R0
SYMATTR InstName C2
SYMATTR Value 1e-6
TEXT -72 280 Left 0 !.model SW SW(Ron=1 Roff=10Meg Vt=0.5Vh=0)
TEXT -74 312 Left 0 !.tran 5

but hardly germane, since what's being discussed is whether the 555's
output tracks the supply and, in your own words:

"The logic levels of the bipolar part don't track the power supply
voltage"

Now, if by that you meant that the output voltage isn't either
precisely Vcc or 0V, then neither does CMOS "track" the supply.

My point is that as the supply voltage varies, so will the output
voltage, so they track regardless of the voltage difference between
them.

As to the effects caused in this circuit by varying the supply
voltage, that's probably better addressed in a different,
non-confrontational thread.

--
JF
 
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