Driver to drive?

Lostgallifreyan · Oct 27, 2011

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:IPmdnZqZtOQ4FTTTnZ2dnUVZ_sydnZ2d@supernews.com:

Ground and VDD both work, but ground is usually best, because the VCO
control voltage is ground-referred. You just need to pull the quiescent
operating point of the phase detector a bit off zero to avoid the flat
spot in the V(phi) curve.

The flat spot is caused by the finite slew rate of the output--as the
phase error approaches zero, the pulse width narrows until it's less
than the rise time. At that point the output becomes a triangle instead
of a trapezoid, so its area starts going as phi**2 instead of phi. Since
the average output current goes as the pulse area, that makes the phase
detector gain go to zero at phi=0, which is A Bad Thing.

Indulge my weakness, please spell it out for me... How much resistor, and
from exactly where, to ground? If I know that I have a better chance of
understanding the rest than deducing it the other way round. The thing about
loops is that all of it might be influenced by any point in it! Causality is
a tad hard to follow in loops...

AFAIK all 18-volt CMOS logic parts are metal gate. That's one of the
usual ways to refer to the general class of CD4XXX, 74CXX, and other old
high voltage CMOS parts.

Good enough for me.

Thanks. That avoids the confusion and leaves HEF4046B
in a context that makes more sense to me.

Phil Hobbs · Oct 27, 2011

On 10/27/2011 01:10 PM, Lostgallifreyan wrote:

Phil Hobbs<pcdhSpamMeSenseless@electrooptical.net> wrote in
news:IPmdnZqZtOQ4FTTTnZ2dnUVZ_sydnZ2d@supernews.com:

Ground and VDD both work. You just need to pull the quiescent
operating point of the phase detector a bit off zero to avoid the flat
spot in the V(phi) curve.

The flat spot is caused by the finite slew rate of the output--as the
phase error approaches zero, the pulse width narrows until it's less
than the rise time. At that point the output becomes a triangle instead
of a trapezoid, so its area starts going as phi**2 instead of phi. Since
the average output current goes as the pulse area, that makes the phase
detector gain go to zero at phi=0, which is A Bad Thing.

Indulge my weakness, please spell it out for me... How much resistor, and
from exactly where, to ground? If I know that I have a better chance of
understanding the rest than deducing it the other way round. The thing about
loops is that all of it might be influenced by any point in it! Causality is
a tad hard to follow in loops...

It depends on the circuit constants. You want the total charge flowing
through the resistor per cycle to equal that contributed by some safe
number T nanoseconds' worth of the phase detector pulling HIGH or LOW.
T is something like 10 for HCMOS at 5V, maybe 50-200 for metal gate,
depending on the supply voltage. A current source is probably better,
but that's getting a bit fancy.

If you have a spectrum analyzer, look at the output with and without the
resistor--maybe use a pot for testing purposes. The change in the
jitter sidebands is pretty dramatic when you pull just outside the deadband.

AFAIK all 18-volt CMOS logic parts are metal gate. That's one of the
usual ways to refer to the general class of CD4XXX, 74CXX, and other old
high voltage CMOS parts.

Good enough for me. Thanks. That avoids the confusion and leaves HEF4046B
in a context that makes more sense to me.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Lostgallifreyan · Oct 27, 2011

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:rZudndP6woK-CDTTnZ2dnUVZ_v-dnZ2d@supernews.com:

It depends on the circuit constants. You want the total charge flowing
through the resistor per cycle to equal that contributed by some safe
number T nanoseconds' worth of the phase detector pulling HIGH or LOW.
T is something like 10 for HCMOS at 5V, maybe 50-200 for metal gate,
depending on the supply voltage. A current source is probably better,
but that's getting a bit fancy.

If you have a spectrum analyzer, look at the output with and without the
resistor--maybe use a pot for testing purposes. The change in the
jitter sidebands is pretty dramatic when you pull just outside the
deadband.

Please can you give a hobbyists guide type starting point? I.E. starting
resistor value to try, and what pin number on a 4046, to connect to ground?
From my perspective, trying to understand the circuit behaviour without that
info, or to depend on using a spectrum analyser I haven't got, is entirely
putting cart before horse.

Martin Brown · Oct 27, 2011

On 27/10/2011 19:00, Lostgallifreyan wrote:

Phil Hobbs<pcdhSpamMeSenseless@electrooptical.net> wrote in
news:rZudndP6woK-CDTTnZ2dnUVZ_v-dnZ2d@supernews.com:

It depends on the circuit constants. You want the total charge flowing
through the resistor per cycle to equal that contributed by some safe
number T nanoseconds' worth of the phase detector pulling HIGH or LOW.
T is something like 10 for HCMOS at 5V, maybe 50-200 for metal gate,
depending on the supply voltage. A current source is probably better,
but that's getting a bit fancy.

If you have a spectrum analyzer, look at the output with and without the
resistor--maybe use a pot for testing purposes. The change in the
jitter sidebands is pretty dramatic when you pull just outside the
deadband.

Please can you give a hobbyists guide type starting point? I.E. starting
resistor value to try, and what pin number on a 4046, to connect to ground?
From my perspective, trying to understand the circuit behaviour without that
info, or to depend on using a spectrum analyser I haven't got, is entirely
putting cart before horse.

Provided you run the VCO at audio frequencies then for the purposes of
testing a realtime spectrum analyser is built into Daqarta and ISTR
there is a 30 day free trial period to see if you like it.

I have no connection with the author other than as an occasional user.
http://www.daqarta.com/

Price is also within reach of electronics hobbyists - it uses the sound
card to digitise the line input on a PC.

--
Regards,
Martin Brown

Jim Thompson · Oct 27, 2011

On Thu, 27 Oct 2011 13:00:37 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:rZudndP6woK-CDTTnZ2dnUVZ_v-dnZ2d@supernews.com:

It depends on the circuit constants. You want the total charge flowing
through the resistor per cycle to equal that contributed by some safe
number T nanoseconds' worth of the phase detector pulling HIGH or LOW.
T is something like 10 for HCMOS at 5V, maybe 50-200 for metal gate,
depending on the supply voltage. A current source is probably better,
but that's getting a bit fancy.

If you have a spectrum analyzer, look at the output with and without the
resistor--maybe use a pot for testing purposes. The change in the
jitter sidebands is pretty dramatic when you pull just outside the
deadband.

Please can you give a hobbyists guide type starting point? I.E. starting
resistor value to try, and what pin number on a 4046, to connect to ground?
From my perspective, trying to understand the circuit behaviour without that
info, or to depend on using a spectrum analyser I haven't got, is entirely
putting cart before horse.

Lostgallifreyan · Oct 27, 2011

Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote in
news:Uxhqq.2591$121.647@newsfe02.iad:

Provided you run the VCO at audio frequencies then for the purposes of
testing a realtime spectrum analyser is built into Daqarta and ISTR
there is a 30 day free trial period to see if you like it.

I have no connection with the author other than as an occasional user.
http://www.daqarta.com/

Thanks for the idea, I'll look into that. I deliberately stay with W98 so I
might be out of luck but if it runs it might be a keeper.

Phil Hobbs · Oct 27, 2011

On 10/27/2011 02:00 PM, Lostgallifreyan wrote:

Phil Hobbs<pcdhSpamMeSenseless@electrooptical.net> wrote in
news:rZudndP6woK-CDTTnZ2dnUVZ_v-dnZ2d@supernews.com:

It depends on the circuit constants. You want the total charge flowing
through the resistor per cycle to equal that contributed by some safe
number T nanoseconds' worth of the phase detector pulling HIGH or LOW.
T is something like 10 for HCMOS at 5V, maybe 50-200 for metal gate,
depending on the supply voltage. A current source is probably better,
but that's getting a bit fancy.

If you have a spectrum analyzer, look at the output with and without the
resistor--maybe use a pot for testing purposes. The change in the
jitter sidebands is pretty dramatic when you pull just outside the
deadband.

Please can you give a hobbyists guide type starting point? I.E. starting
resistor value to try, and what pin number on a 4046, to connect to ground?
From my perspective, trying to understand the circuit behaviour without that
info, or to depend on using a spectrum analyser I haven't got, is entirely
putting cart before horse.

Sure, if you post your loop filter component values and operating
frequency. If you have a scope, you can look at the PD2 output and
adjust the resistor so that the positive pulse is always at least 100 ns
wide. That'll give you a bit of frequency-dependent phase error, but
that's usually not a big worry in a lowish-performance PLL.

What happens is that the loop oscillates with a small amplitude around
the null, sort of like the temperature in your house as the thermostat
kicks on and off.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Lostgallifreyan · Oct 27, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:lobja7tneuhd9anv746aeigjcfichn38ol@4ax.com:

At audio I doubt that you'll know it even exists because you loop
filter corner will be quite low compared to the device delay time.

Now that I DID understand right on first sight.

I have to say it's not
something I noticed in my design, so far as I know. One quirk I saw was a
lock indicator based on the outputs of both comparators failing to indicate
lock when the audible output proved there was a lock. I don't know what that
means... I considered it might mean that PC2 was basing output on a
harmonic. (I'm using PC1 in the loop, so I was never sure what PC2 would be
doing at the same time until I considered using it for part of the lock
indicator).

Jim Thompson · Oct 27, 2011

On Thu, 27 Oct 2011 18:31:02 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:lobja7tneuhd9anv746aeigjcfichn38ol@4ax.com:

At audio I doubt that you'll know it even exists because you loop
filter corner will be quite low compared to the device delay time.

Now that I DID understand right on first sight. I have to say it's not
something I noticed in my design, so far as I know.

Awwwwh! You mean you're not audiophool enough to fret over a few
hundred pico-seconds of jitter ?

One quirk I saw was a
lock indicator based on the outputs of both comparators failing to indicate
lock when the audible output proved there was a lock. I don't know what that
means...

Most lock detectors don't do anything useful but give marketers
something to brag about.

I considered it might mean that PC2 was basing output on a
harmonic. (I'm using PC1 in the loop, so I was never sure what PC2 would be
doing at the same time until I considered using it for part of the lock
indicator).

Lostgallifreyan · Oct 28, 2011

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:4EA9E8BD.6080203@electrooptical.net:

Please can you give a hobbyists guide type starting point? I.E.
starting resistor value to try, and what pin number on a 4046, to
connect to ground?
From my perspective, trying to understand the circuit behaviour
without that
info, or to depend on using a spectrum analyser I haven't got, is
entirely putting cart before horse.

Sure, if you post your loop filter component values and operating
frequency. If you have a scope, you can look at the PD2 output and
adjust the resistor so that the positive pulse is always at least 100 ns
wide. That'll give you a bit of frequency-dependent phase error, but
that's usually not a big worry in a lowish-performance PLL.

What happens is that the loop oscillates with a small amplitude around
the null, sort of like the temperature in your house as the thermostat
kicks on and off.

Thanks.

LPF is currently 100K with 33nF but there is also a 10K in series
with the 33nF. It's at least a year or two since I last worked on that
pindecked layout so I can't remember why the hell I did that with the 10K but
it seemed to work at the time. Frequencies vary, but currently constrained to
those a person whistling can make. (I'd been filtering the input with
bandpass from 300Hz to 3KHz at one point, though I may eventually want more
to see if this thing can track other musical sources).

I have a 100 MHz scope, so I'll look at that PC2 output. I actually use only
PC1 in my loop which may be why I never saw the dead zone thing (except in a
silly zombie movie iirc...). I do intend use of PC2 in a lock indicator which
has been slightly erratic so if that's due to this problem I'll definitely
examine it.

Which pin on the 4046 to ground via the resistor, though? I'm asking the dumb
question because the answer should prevent me making any number of stupid
mistakes if I fail to grasp what you already told me... I mentioned the VCO
output but I am only guessing, no-one told me so far unless I missed
something.

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 19:17:28 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:4EA9E8BD.6080203@electrooptical.net:

Please can you give a hobbyists guide type starting point? I.E.
starting resistor value to try, and what pin number on a 4046, to
connect to ground?
From my perspective, trying to understand the circuit behaviour
without that
info, or to depend on using a spectrum analyser I haven't got, is
entirely putting cart before horse.

Sure, if you post your loop filter component values and operating
frequency. If you have a scope, you can look at the PD2 output and
adjust the resistor so that the positive pulse is always at least 100 ns
wide. That'll give you a bit of frequency-dependent phase error, but
that's usually not a big worry in a lowish-performance PLL.

What happens is that the loop oscillates with a small amplitude around
the null, sort of like the temperature in your house as the thermostat
kicks on and off.

Thanks. LPF is currently 100K with 33nF but there is also a 10K in series
with the 33nF. It's at least a year or two since I last worked on that
pindecked layout so I can't remember why the hell I did that with the 10K but
it seemed to work at the time.

A VCO, in itself, is a 1/s function. The filter adds another 1/s, so
a zero (your 10K) is needed for loop stability.

Frequencies vary, but currently constrained to
those a person whistling can make. (I'd been filtering the input with
bandpass from 300Hz to 3KHz at one point, though I may eventually want more
to see if this thing can track other musical sources).

I have a 100 MHz scope, so I'll look at that PC2 output. I actually use only
PC1 in my loop which may be why I never saw the dead zone thing (except in a
silly zombie movie iirc...). I do intend use of PC2 in a lock indicator which
has been slightly erratic so if that's due to this problem I'll definitely
examine it.

Which pin on the 4046 to ground via the resistor, though? I'm asking the dumb
question because the answer should prevent me making any number of stupid
mistakes if I fail to grasp what you already told me... I mentioned the VCO
output but I am only guessing, no-one told me so far unless I missed
something.

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:n7rja7duecd2lrl031gepbp2fn6ireveud@4ax.com:

Awwwwh! You mean you're not audiophool enough to fret over a few
hundred pico-seconds of jitter ?

Hell no.

I just lack a certain conceptual proportion when it comes to
arcane thingers like PLL's..

About the lock detector, there IS a use for me... If the input goes loud and
noisy, the VCO shoots as high as the circuit config will let it. Imagine that
in a live performance. >

I did see that when this happens, the lock
indicator can usefully inhibit some later device to prevent output. I tried
thinking of other ways to solve this, but the lock indicator did better than
anythign I came up with, and very cheaply. It's just not always 100%. It
always safely mutes for bad input, but does not always indicate when good
input and lock are present. This might be a PC2-and-harmonic thing, or some
basic flaw in the indicator circuit.

Lostgallifreyan · Oct 28, 2011

George Herold <gherold@teachspin.com> wrote in news:d420780a-8348-4cce-a2d4-
0480e27eb549@s7g2000yqa.googlegroups.com:

Do you have a digital 'scope? They have a so-so spectrum analyzer.
As far as phase locked loops, I don't know the 4046. But there are a
few different approaches. The AoE is as good a place to start as
any.

Indeed. That, and RM Marston's book on linear IC's got me very interested in
the 4046. I got most of my starting points from those two, and a bit of trial
and error.

No digital scope, but I think Phil Hobbs' post said I'd be ok with an analog
scope, if fast enough. (Mine is, I think, more than I'll need for this).

I'm very interested in the use of the 4046 as VCO. At the moment I'm
using one to drive a stepped sine thingie. I've been starring at the
spec sheet curves wondering if there's a sweet spot somewhere in R/C
space. At the moment I've got R=20k and C=470pF.

As far as I can tell, most 4046 VCO's will be a lot more linear with 100K to
1Meg with a supply voltage as high as they'll take safely, but the last thing
I am is an authoroty on this...

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 19:23:41 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:n7rja7duecd2lrl031gepbp2fn6ireveud@4ax.com:

Awwwwh! You mean you're not audiophool enough to fret over a few
hundred pico-seconds of jitter ?

Hell no. I just lack a certain conceptual proportion when it comes to
arcane thingers like PLL's..

About the lock detector, there IS a use for me... If the input goes loud and
noisy, the VCO shoots as high as the circuit config will let it.

What is it you're trying to do? Sub-bass? Chasing lights? What? I
did all that s!@# ~40 years ago ;-)

Imagine that
in a live performance. > I did see that when this happens, the lock
indicator can usefully inhibit some later device to prevent output. I tried
thinking of other ways to solve this, but the lock indicator did better than
anythign I came up with, and very cheaply. It's just not always 100%. It
always safely mutes for bad input, but does not always indicate when good
input and lock are present. This might be a PC2-and-harmonic thing, or some
basic flaw in the indicator circuit.

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:satja71a2dormkbnrl5ae3nmblsqnvvt61@4ax.com:

Thanks. LPF is currently 100K with 33nF but there is also a 10K in
series with the 33nF. It's at least a year or two since I last worked on
that pindecked layout so I can't remember why the hell I did that with
the 10K but it seemed to work at the time.

A VCO, in itself, is a 1/s function. The filter adds another 1/s, so
a zero (your 10K) is needed for loop stability.

Ok, I got some more on that from Art of Electronics just now, which I'd
forgotten about. RM Marston shows that resistor too, though didn't explain
it.

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:s3uja71sjd1kluivcb5u9krh05l66cli6b@4ax.com:

What is it you're trying to do? Sub-bass? Chasing lights? What? I
did all that s!@# ~40 years ago ;-)

Whistle to MIDI convertor. Seriously.

I actually got fairly good at
whistling. I can play a bass guitar fairly well now, and keyboard (with right
hand only, poor co-ordination for both), but whistling will allow a very good
solo line, and combining that with keyborad via MIDI might give a lead
guitarist a hell of a run for their money! A prospect of an instrument that
fine has to be worth some effort to acheive. Dieter Doupfer is planning
somethign similar using all digital derivations, but his project is forver on
the back burner.

As I'll settle for something less than ideal for many
input signals, and already have some good work done, I can hopefulyl get by.
I still rely on one of his inventions, which allows a control voltage to
fluently scale across several octaves of MIDI to make a monophonic synth play
a clean sweep across the entire key range. I had to modify the gadget
slightly to do this, but he solves the biggest problem for me, all I have to
do is give it a voltage it can use.

No matter how many times people have tried to make this basic notion a
reality, it still doesn't exist commercially. Since Bob Moog's log amp, not
all that much has changed. At least in the LOG112 I can get that bit ready
made with more accuracy and stability than I'll ever need.

The weak link
seems to be the VCO in the PLL, but maybe it's good enough if I can get
0.25%. A brain can usually make itself part of a live player's feedback loop
somehow. Violinists have always seemed to manage.

Lostgallifreyan · Oct 28, 2011

Lostgallifreyan <no-one@nowhere.net> wrote in
news:Xns9F8C142AA81EEzoodlewurdle@216.196.109.145:

Dieter Doupfer

Doepfer.

Phil Hobbs · Oct 28, 2011

On 10/27/2011 08:17 PM, Lostgallifreyan wrote:

Phil Hobbs<pcdhSpamMeSenseless@electrooptical.net> wrote in
news:4EA9E8BD.6080203@electrooptical.net:

Please can you give a hobbyists guide type starting point? I.E.
starting resistor value to try, and what pin number on a 4046, to
connect to ground?
From my perspective, trying to understand the circuit behaviour
without that
info, or to depend on using a spectrum analyser I haven't got, is
entirely putting cart before horse.

Sure, if you post your loop filter component values and operating
frequency. If you have a scope, you can look at the PD2 output and
adjust the resistor so that the positive pulse is always at least 100 ns
wide. That'll give you a bit of frequency-dependent phase error, but
that's usually not a big worry in a lowish-performance PLL.

What happens is that the loop oscillates with a small amplitude around
the null, sort of like the temperature in your house as the thermostat
kicks on and off.

Thanks. LPF is currently 100K with 33nF but there is also a 10K in series
with the 33nF. It's at least a year or two since I last worked on that
pindecked layout so I can't remember why the hell I did that with the 10K but
it seemed to work at the time. Frequencies vary, but currently constrained to
those a person whistling can make. (I'd been filtering the input with
bandpass from 300Hz to 3KHz at one point, though I may eventually want more
to see if this thing can track other musical sources).

I have a 100 MHz scope, so I'll look at that PC2 output. I actually use only
PC1 in my loop which may be why I never saw the dead zone thing (except in a
silly zombie movie iirc...). I do intend use of PC2 in a lock indicator which
has been slightly erratic so if that's due to this problem I'll definitely
examine it.

Which pin on the 4046 to ground via the resistor, though? I'm asking the dumb
question because the answer should prevent me making any number of stupid
mistakes if I fail to grasp what you already told me... I mentioned the VCO
output but I am only guessing, no-one told me so far unless I missed
something.

Try 10M from the PD2 output to ground.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 19:58:59 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:s3uja71sjd1kluivcb5u9krh05l66cli6b@4ax.com:

What is it you're trying to do? Sub-bass? Chasing lights? What? I
did all that s!@# ~40 years ago ;-)

Whistle to MIDI convertor. Seriously. I actually got fairly good at
whistling. I can play a bass guitar fairly well now, and keyboard (with right
hand only, poor co-ordination for both), but whistling will allow a very good
solo line, and combining that with keyborad via MIDI might give a lead
guitarist a hell of a run for their money! A prospect of an instrument that
fine has to be worth some effort to acheive. Dieter Doupfer is planning
somethign similar using all digital derivations, but his project is forver on
the back burner. As I'll settle for something less than ideal for many
input signals, and already have some good work done, I can hopefulyl get by.
I still rely on one of his inventions, which allows a control voltage to
fluently scale across several octaves of MIDI to make a monophonic synth play
a clean sweep across the entire key range. I had to modify the gadget
slightly to do this, but he solves the biggest problem for me, all I have to
do is give it a voltage it can use.

No matter how many times people have tried to make this basic notion a
reality, it still doesn't exist commercially. Since Bob Moog's log amp, not
all that much has changed. At least in the LOG112 I can get that bit ready
made with more accuracy and stability than I'll ever need. The weak link
seems to be the VCO in the PLL, but maybe it's good enough if I can get
0.25%. A brain can usually make itself part of a live player's feedback loop
somehow. Violinists have always seemed to manage.

Lostgallifreyan · Oct 28, 2011

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:4EAA000F.6040106@electrooptical.net:

Try 10M from the PD2 output to ground.

Thanks. I got to stop now. Late, and my eyes actually hurt...

Driver to drive?

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