Re: Where are all the ESR meters?

On Sun, 22 Jul 2007 19:39:36 GMT, Fred Bloggs <nospam@xxxxxxxxxx>
wrote:



John Larkin wrote:
On Sun, 22 Jul 2007 15:57:37 GMT, Fred Bloggs <nospam@xxxxxxxxxx>
wrote:



Jim Thompson wrote:

On Sun, 22 Jul 2007 04:24:21 -0700, Winfield <winfieldhill@xxxxxxxxx>
wrote:



Jim Thompson wrote:


Winfield wrote:



I'll post mine, when I get enough energy to transcribe
it from my paper scratchings, calculations and notes.
Remember, it must be four terminal, and handle high DC
voltages when probing in-circuit storage capacitors.

How high is "high"?

Perhaps a better question is, how big is big?

Several designs we've been considering have a
pair of diodes to discharge the test capacitor
and limit the circuit voltages, but I've heard
these can fail with large, charged capacitors.

I think the issue isn't necessarily how high
the voltage (tube amplifiers get to hundreds
of volts), or how high the current delivered,
but how much energy is going to be dissipated
in the protection components that discharge
the guilty capacitor.

I'd say the answer is, the size of two fists.
I think we're talking about ~ 100J of energy.
Isn't that more than enough to blow out a
common glass diode and/or a 1/4-watt resistor?


Should be enough to crank you over a few times ;-)

...Jim Thompson

WH is stalling... input protection has little to do with a basic
measurement architecture. I had no idea this little project would be so
difficult for everyone:-)



Interesting that for a proposed "group design", hardly anybody is
willing to make a first step. The psychology of group design is
fascinating, and it turns out that an audience is a huge inhibition;
people tend to not expose ideas if they fear they are imperfect, and
might give some nit-picker grounds for public criticism.

Brainstorming is delicate because people are fragile. At my place, we
scribble goofy ideas on a whiteboard, do a lot of stupid stuff (don't
distinguish between circuit-as-proposal and circuit-as-joke), argue
and laugh a lot, and sometimes come up with brilliance, with no way to
tell who gets the credit. Some people just can't play at this game.

John


Well whatever...the task is straightforward and does not require a great
amount of ingenuity. The ingenuity comes in deciding the functionality
of the meter. In my opinion there is nothing to accomplish by going half
way to an impedance analyzer, there are already plenty of compact and
fully functional products in that niche. The key is to produce the
simplest possible design that measures ESR, if something else comes free
along with that without introducing one iota more of complexity then
fine, but if it requires one speck of dedicated hardware not useful for
determining ESR then it goes. This will require that you discover
something inherent to ESR that allows for a very simple circuit
architecture. That is all the help I am going to give you at this stage:-)

Thanks for the excellent illustration of my point. You are far more
concerned about your ego than you are about the technology. Probably
that explains why you don't design electronics.

There's a great irony here; that is all the help I am going to give
you at this stage.

John

.

Relevant Pages

  • Re: Where are all the ESR meters?
    ... Jim Thompson wrote: ... voltages when probing in-circuit storage capacitors. ... Interesting that for a proposed "group design", ... I already have a perfectly good ESR meter that I built from a kit ...
    (sci.electronics.design)
  • Re: Where are all the ESR meters?
    ... voltages when probing in-circuit storage capacitors. ... The psychology of group design is ... determining ESR then it goes. ...
    (sci.electronics.design)
  • Re: Where are all the ESR meters?
    ... Jim Thompson wrote: ... voltages when probing in-circuit storage capacitors. ... Interesting that for a proposed "group design", ...
    (sci.electronics.design)
  • Re: Where are all the ESR meters?
    ... voltages when probing in-circuit storage capacitors. ... The key is to produce the simplest possible design that measures ESR, if something else comes free along with that without introducing one iota more of complexity then fine, but if it requires one speck of dedicated hardware not useful for determining ESR then it goes. ...
    (sci.electronics.design)
  • Re: Where are all the ESR meters?
    ... voltages when probing in-circuit storage capacitors. ... The key is to produce the simplest possible design that measures ESR, if something else comes free along with that without introducing one iota more of complexity then fine, but if it requires one speck of dedicated hardware not useful for determining ESR then it goes. ...
    (sci.electronics.design)
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