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capacitor.Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
What is it that you do at Novatech?"Mark Folsom" <folsom_snip_man@redshift.com> writes:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the"Mark Folsom" <folsom_snip_man@redshift.com> writes:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
Correct.Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the
opposite of what I asked for.
For the first 100 to 1000ms of operation, the powered circuit draws about 5In article <vtchsveg0c4c09@corp.supernews.com>,
Mark Folsom <folsom_snip_man@redshift.com> wrote:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is
applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the
opposite of what I asked for.
Correct.
"Inductor" is one possible answer, which might work if you don't need
a particularly "sharp" turn-on, and if you're simply concerned about
passing DC.
What I envisioned, if only we had room, is an RC circuit connected through aAnother approach would be to use a FET, with a suitable gate voltage
being applied through an R/C circuit of some sort... or perhaps using
a bidirectional FET-type optocoupler.
"Steven Swift" <novatech@eskimo.com> wrote in message
news:br5cn3$q2u$1@eskinews.eskimo.com...
"Mark Folsom" <folsom_snip_man@redshift.com> writes:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the
opposite of what I asked for.
Mark Folsom
7 posts in the thread and it's still not at all clear what you want."Dave Platt" <dplatt@radagast.org> wrote in message
news:vtcige6k0q6m4b@corp.supernews.com...
In article <vtchsveg0c4c09@corp.supernews.com>,
Mark Folsom <folsom_snip_man@redshift.com> wrote:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is
applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the
opposite of what I asked for.
Correct.
"Inductor" is one possible answer, which might work if you don't need
a particularly "sharp" turn-on, and if you're simply concerned about
passing DC.
For the first 100 to 1000ms of operation, the powered circuit draws about 5
microamps. The initial voltage, from which we would like to protect the
powered circuit, could be from 50 to 60 volts. After about 50 microseconds,
drawing off a tiny bit of charge will bring the voltage down to half of its
initial value, which is acceptable to the powered circuit. Since we need
this to be tiny, an inductor is unsuitable.
Another approach would be to use a FET, with a suitable gate voltage
being applied through an R/C circuit of some sort... or perhaps using
a bidirectional FET-type optocoupler.
What I envisioned, if only we had room, is an RC circuit connected through a
zener to the gate of an SCR. The capacitor would charge until it reached
the threshold of the zener and then switch the SCR on--and it would draw off
the bit of charge needed to pull the voltage down. A small surface mount
chip with this set of components or an operational equivalent would help a
lot.
Mark Folsom
Well, inductor would be closer, but the OP is probably looking for"Mark Folsom" <folsom_snip_man@redshift.com> writes:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is applied,
like maybe 100 microseconds? If so, what's it called?
capacitor.
I think it's pretty clear what I want. If there's something specific youMark Folsom wrote:
"Dave Platt" <dplatt@radagast.org> wrote in message
news:vtcige6k0q6m4b@corp.supernews.com...
In article <vtchsveg0c4c09@corp.supernews.com>,
Mark Folsom <folsom_snip_man@redshift.com> wrote:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is
applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the
opposite of what I asked for.
Correct.
"Inductor" is one possible answer, which might work if you don't need
a particularly "sharp" turn-on, and if you're simply concerned about
passing DC.
For the first 100 to 1000ms of operation, the powered circuit draws
about 5
microamps. The initial voltage, from which we would like to protect the
powered circuit, could be from 50 to 60 volts. After about 50
microseconds,
drawing off a tiny bit of charge will bring the voltage down to half of
its
initial value, which is acceptable to the powered circuit. Since we
need
this to be tiny, an inductor is unsuitable.
Another approach would be to use a FET, with a suitable gate voltage
being applied through an R/C circuit of some sort... or perhaps using
a bidirectional FET-type optocoupler.
What I envisioned, if only we had room, is an RC circuit connected
through a
zener to the gate of an SCR. The capacitor would charge until it
reached
the threshold of the zener and then switch the SCR on--and it would draw
off
the bit of charge needed to pull the voltage down. A small surface
mount
chip with this set of components or an operational equivalent would help
a
lot.
Mark Folsom
7 posts in the thread and it's still not at all clear what you want.
Way too many "about", 10:1 time interval range, tiny bit of charge...
Just clamp the voltage with a zener.
mike
Mark,I think it's pretty clear what I want. If there's something specific you
don't understand, maybe you could ask. Unlike most electronic applications,
this one needs to avoid throwing away the energy that would be lost in
clamping with a zener. I may seem stupid to you, but I already thought of
clamping with a zener.
If you think 7 posts is too much, you can stop reading.
Thanks,
Mark Folsom
That's often the problem. Customer is SURE he knows what he wants."mike" <spamme0@juno.com> wrote in message news:3FD66A52.7020609@juno.com...
Mark Folsom wrote:
"Dave Platt" <dplatt@radagast.org> wrote in message
news:vtcige6k0q6m4b@corp.supernews.com...
In article <vtchsveg0c4c09@corp.supernews.com>,
Mark Folsom <folsom_snip_man@redshift.com> wrote:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is
applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the
opposite of what I asked for.
Correct.
"Inductor" is one possible answer, which might work if you don't need
a particularly "sharp" turn-on, and if you're simply concerned about
passing DC.
For the first 100 to 1000ms of operation, the powered circuit draws
about 5
microamps. The initial voltage, from which we would like to protect the
powered circuit, could be from 50 to 60 volts. After about 50
microseconds,
drawing off a tiny bit of charge will bring the voltage down to half of
its
initial value, which is acceptable to the powered circuit. Since we
need
this to be tiny, an inductor is unsuitable.
Another approach would be to use a FET, with a suitable gate voltage
being applied through an R/C circuit of some sort... or perhaps using
a bidirectional FET-type optocoupler.
What I envisioned, if only we had room, is an RC circuit connected
through a
zener to the gate of an SCR. The capacitor would charge until it
reached
the threshold of the zener and then switch the SCR on--and it would draw
off
the bit of charge needed to pull the voltage down. A small surface
mount
chip with this set of components or an operational equivalent would help
a
lot.
Mark Folsom
7 posts in the thread and it's still not at all clear what you want.
Way too many "about", 10:1 time interval range, tiny bit of charge...
Just clamp the voltage with a zener.
mike
I think it's pretty clear what I want.
Nobody said you were stupid, just unspecified.don't understand, maybe you could ask. Unlike most electronic applications,
this one needs to avoid throwing away the energy that would be lost in
clamping with a zener. I may seem stupid to you, but I already thought of
clamping with a zener.
If it's really just a tiny bit of charge, why is clamping such adrawing off a tiny bit of charge will bring the voltage down to half
of its initial value.
I'm trying to be helpful. We're up to 10 posts and there's stillIf you think 7 posts is too much, you can stop reading.
Thanks,
Mark Folsom
I have two capacitors that I am charging in series, with a lot of noise, inMark Folsom wrote:
"mike" <spamme0@juno.com> wrote in message
news:3FD66A52.7020609@juno.com...
Mark Folsom wrote:
"Dave Platt" <dplatt@radagast.org> wrote in message
news:vtcige6k0q6m4b@corp.supernews.com...
In article <vtchsveg0c4c09@corp.supernews.com>,
Mark Folsom <folsom_snip_man@redshift.com> wrote:
Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is
applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
capacitor.
but I think you meant something more detailed.
A capacitor conducts when voltage is applied, then stops. That's the
opposite of what I asked for.
Correct.
"Inductor" is one possible answer, which might work if you don't need
a particularly "sharp" turn-on, and if you're simply concerned about
passing DC.
For the first 100 to 1000ms of operation, the powered circuit draws
about 5
microamps. The initial voltage, from which we would like to protect
the
powered circuit, could be from 50 to 60 volts. After about 50
microseconds,
drawing off a tiny bit of charge will bring the voltage down to half of
its
initial value, which is acceptable to the powered circuit. Since we
need
this to be tiny, an inductor is unsuitable.
Another approach would be to use a FET, with a suitable gate voltage
being applied through an R/C circuit of some sort... or perhaps using
a bidirectional FET-type optocoupler.
What I envisioned, if only we had room, is an RC circuit connected
through a
zener to the gate of an SCR. The capacitor would charge until it
reached
the threshold of the zener and then switch the SCR on--and it would
draw
off
the bit of charge needed to pull the voltage down. A small surface
mount
chip with this set of components or an operational equivalent would
help
a
lot.
Mark Folsom
7 posts in the thread and it's still not at all clear what you want.
Way too many "about", 10:1 time interval range, tiny bit of charge...
Just clamp the voltage with a zener.
mike
I think it's pretty clear what I want.
That's often the problem. Customer is SURE he knows what he wants.
But that's usually not what he asks for. It's the old communication
problem. Getting the requirements out is the hardest part of any
project. I called the psychic hotline, but Miss Cleo didn't know either.
If there's something specific you
don't understand, maybe you could ask. Unlike most electronic
applications,
this one needs to avoid throwing away the energy that would be lost in
clamping with a zener. I may seem stupid to you, but I already thought
of
clamping with a zener.
Nobody said you were stupid, just unspecified.
Here's what you stated:
drawing off a tiny bit of charge will bring the voltage down to half
of its initial value.
If it's really just a tiny bit of charge, why is clamping such a
problem? If you had your magic device, how would that tiny bit of
charge be of benefit??? Stated another way, how are you gonna get the
voltage down without drawing off that tiny bit of charge?
Something like this:Is there a (preferably tiny surface mount) device that starts out
non-conducting and then conducts a short time after a voltage is applied,
like maybe 100 microseconds? If so, what's it called?
Mark Folsom
Hmmmmm! In your order:Is that clear yet? I'm not going to disclose the whole system design or
the end use.
Well, I was told I should use a capacitor, that I should just clamp theRE:
Is that clear yet? I'm not going to disclose the whole system design or
the end use.
Hmmmmm! In your order:
Yes.
I think the end use is somewhat clear.
You seem to have a chip on your shoulder. That's not nice when asking for
help.
Well, I was told I should use a capacitor, that I should just clamp the
voltage with a zener, that I should use an inductor, etc., etc.
Meanwhile,
I've given more and more detail on how the item would be used, and most of
the comments I get back offer nothing whatever of use--either you haven't
read what I've posted, or you don't understand what I'm trying to do even
after you've read it. Maybe the vast majority of you don't have a clue
and
you're just jerking me around for your own amusement. Being nice to a
bunch
of ignorant jerks isn't likely to be terribly productive in this context.
Ok, so I'm playing 20-questions, reverse engineering a secret design to"Dbowey" <dbowey@aol.com> wrote in message
news:20031210164113.07996.00000531@mb-m16.aol.com...
RE:
Is that clear yet? I'm not going to disclose the whole system design or
the end use.
Hmmmmm! In your order:
Yes.
I think the end use is somewhat clear.
You seem to have a chip on your shoulder. That's not nice when asking for
help.
Well, I was told I should use a capacitor, that I should just clamp the
voltage with a zener, that I should use an inductor, etc., etc. Meanwhile,
I've given more and more detail on how the item would be used, and most of
the comments I get back offer nothing whatever of use--either you haven't
read what I've posted, or you don't understand what I'm trying to do even
after you've read it. Maybe the vast majority of you don't have a clue and
you're just jerking me around for your own amusement. Being nice to a bunch
of ignorant jerks isn't likely to be terribly productive in this context.
Mark Folsom
Well, if you had given sufficient detail in the first place, youWell, I was told I should use a capacitor, that I should just clamp the
voltage with a zener, that I should use an inductor, etc., etc. Meanwhile,
I've given more and more detail on how the item would be used, and most of
the comments I get back offer nothing whatever of use--either you haven't
read what I've posted, or you don't understand what I'm trying to do even
after you've read it. Maybe the vast majority of you don't have a clue and
you're just jerking me around for your own amusement. Being nice to a bunch
of ignorant jerks isn't likely to be terribly productive in this context.