Electronics > Metrology

Electrostatic Voltmeter Verification

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ultrasmurf:
Guys, I just got myself some electro static measurement probe and PCB attached to it. Suppose to be working, and I can probably check the output easily. Question is, how do I know it is measuring somewhat in the ballpark region ? Doesn't need to be 1% accurate but not in the 50% region as well.. I'm thinking of rubbing my hair... but what will be the reading for that ? 7kV ? or will it be a large possible range that is quite useless to see whether the device can indeed work and measure somewhat reliably ?

doktor pyta:
AFAIK it is the compensating electrostatic voltmeter (it has built in positive and negative high voltage DC/DC converters). That is why the calibration should be easy, because the distance from object to probe is not affecting the measurement (as long as it does not disturb the electrostatic field).
TREK document http://www.trekj.com/products/pdf/3001_Vibrating_Probe.pdf

So take a metal plate MUCH larger than the probe dimension and connect it to a known DC high voltage. You may also use a metal can with no sharp edges instead of the plate. Place the probe say 2cm from the probe or inside the can. Both: TREK board and the voltage source must be grounded to the same point. The probe may be at high potential so be careful.

EDIT: this patent describes the conception and the error vs. distance issue: http://www.google.com/patents/US20080079435

ultrasmurf:
Thanks for the link. Was reading it and bunch of other article about kelvin probe. Anyho, board was broken, the optocoupler was shot. Ordering replacement part for it...

I have a hene laser setup, so pointing the probe somewhat close to the anode side of the laser tube should give me a reading right ? And I know the tube should be lit at about 1KV.

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