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Re: KV meter
On Sun, 08 Oct 2000 11:55:14 -0600, you wrote:
>Original poster: "David Euans" <davidwe-at-telocity-dot-com>
>I am trying to build a 50 KV high voltage meter for directly measuring
>the voltage from my various high voltage transformers. I have tried
>using a 100 microamp full scale DC meter with one 250 (32 KV) megohm
>resistor on each leg and an 80 KV diode string (four 20 KV units)
>directly off of one side of a 9 KV neon sign transformer in series with
>one of the 250 megohm resistors, but I get faulty readings each time.
>Using Ohm's law, 500 megohms should yield 18 microamps at 9 KV, but I am
>only getting about 5 microamps of output. I have tried several
>different diodes, but get similar results regardless. The NST is
>working properly. Am I missing something here? The diodes seem to be
>dropping too much voltage. If anyone knows how to properly set up a
>voltage divider circuit for measuring AC with a DC meter, I would love
>to hear it. To illustrate, my circuit is as follows:
At these voltages, capacitance effects will probably be significant.
Instead of a HV rectifier, you could probably use a low-voltage
bridge-rec across the meter, or a shunt-diode arrangement.
(use fixed-pitch font)
| V D2
D2 compensates for the forward voltage-drop of D1