On 24 March 2018 at 17:34, Jeremy Nichols wrote:
> I made a high-value resistor using motor oil and a couple of stainless
> bolts. It worked for what I was doing (testing an HP-425A
> Microvolt-Ammeter) but calculated as only 8,500 Megohms.
>
> Jeremy
>
I had some discussions
On 03/22/2018 09:07 PM, Bob Albert via volt-nuts wrote:
> I found several electrostatic voltmeters on ebay. The brand I remember is
> Sensitive Research.
I have an electrostatic voltmeter (photo attached) that I no longer use
that I'd part with for $50. This thing is big and heavy so
I made a high-value resistor using motor oil and a couple of stainless
bolts. It worked for what I was doing (testing an HP-425A
Microvolt-Ammeter) but calculated as only 8,500 Megohms.
Jeremy
On Sat, Mar 24, 2018 at 10:18 AM Mark Sims wrote:
> Many years ago, there was
Many years ago, there was an article (in Popular Electronics?) that needed a
very high value resistor. They built it by drawing a line between two
terminals with Higgins India Ink. No idea if the ink is still made the way it
was 50 years ago...
> So how does one make ones
Regarding making your own extreme high-value resistors - any object that
has insulators and leads but with nothing connected inside will have
some high R that can be perhaps be measured, but won't be stable against
environment effects on the outer surfaces. There's not much point to
I'm guessing the application relates back to your leaf electrometer
project discussed earlier - trying to assess how the bias charge on the
capacitor holds up from leakage and use of the instrument. If this is
the case, then it's for a one-time use for design of the item, so
shouldn't be too
Vibrating capacitor non contact field probe in feedback loop to create a
voltage follower:
https://www.monroe-electronics.com/ESD/pdf/244a_m.pdf
Bruce
>
> On 23 March 2018 at 15:12 Neville Michie wrote:
>
> Improvise by holding a metal disk over an electronic
Improvise by holding a metal disk over an electronic balance and measuring the
force of attraction.
Calibrate it with a lower known voltage.
cheers,
Neville Michie
> On 23 Mar 2018, at 12:58, Dr. David Kirkby
> wrote:
>
> On 23 March 2018 at 01:49, kc9ieq via
I guess I don't see what the issue is. No, impedance is not infinate when not
nulled, but this is why V supply #2 Is adjustable by whatever convenient means.
Rough adjust, connect, adjust for null, measure. Rinse and repeat. If it
were my project, I'd just run up an HV transformer on a
On 23 March 2018 at 01:49, kc9ieq via volt-nuts wrote:
> How about using (or building) an additional 2kV power supply and a
> sensitive meter movement like a differential voltmeter, adjusting
> for/measuring the null? Impedance at null will be theoretically infinate,
>
How about using (or building) an additional 2kV power supply and a sensitive
meter movement like a differential voltmeter, adjusting for/measuring the null?
Impedance at null will be theoretically infinate, current will be
theoretically zero, and you can measure/monitor the voltage of your
On 23 March 2018 at 01:07, Bob Albert via volt-nuts
wrote:
> I found several electrostatic voltmeters on ebay. The brand I remember
> is Sensitive Research.
> Bob
>
So something like this?
How about using a high voltage probe that used to be commonly used to measure
anode voltages of TV picture tubes. There were probes that had a KV meter built
into the probe and there are ones that were used with VOM'S.
Joe
K3WRY
In a message dated 3/22/2018 8:59:08 PM Eastern Standard Time,
The part I struggle with is “make one” as T ohm meters are ridiculously
sensitive to things like fingerprints, for example. I had a hard time just
putting cables together that had the particular… I was going to say insulation,
but it was more than that, basically everything is important and
I found several electrostatic voltmeters on ebay. The brand I remember is
Sensitive Research.
Bob
On Thursday, March 22, 2018, 6:00:39 PM PDT, Bob Albert via volt-nuts
wrote:
What about an electrostatic voltmeter? Those have been around for decades
and draw
What about an electrostatic voltmeter? Those have been around for decades and
draw zero static current. You didn't indicate how accurate your measurement
needs to be. I am trying to recall the maker of the unit, I think ESI but not
sure.
They were somewhat popular in the 1950s as I recall
Electrostatic voltmeter?
Either the classical version or the modern electronic variant perhaps?
Bruce
>
> On 23 March 2018 at 13:33 "Dr. David Kirkby"
> wrote:
>
> I want to measure a high voltage, but put minimal load on the circuit.
> Looking at
I want to measure a high voltage, but put minimal load on the circuit.
Looking at the Keithley electrometers, the input resistance is at least 200
T ohms, but they tend to have a maximum of 200 V FSD.
A 2000 V source, and a 200 T ohm resistor gives a current of 10 pA, which
itself is easy to
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