Measuring the high voltage plate Voltage
Measuring the high voltage plate on RF amplifiers.
How can you measure the plate voltage on a amplifier?
I looked at some HV probes that can be used with multimeters, but there seems to be a problem with them handling the current. So what to do to accomplish this.
This is what I have looked at.
FLUKE 80K-6 HIGH VOLTAGE PROBE for MULTI-METER METERS!
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That probe will work.
Keep in mind it will only be accurate with a meter that has a 10MΩ input impedance.
Now my mistakes travel at the speed of light!
Probably work with the correct meter...
But note that is safety rated for use on devices with HV
supplies that are designed to deliver very low currents.
You might consider using a series network of resistors to scale down the voltage. The really cheap way is to use the existing bleeder resistors. Perhaps the most accurate way is to buy a lot of precision resistors and connect identical resistors in series--and then calibrate them with a lower voltage. You should measure the voltage across the resistor closest to ground. They should all heat up identically.
If you're measuring voltage, that has nothing to do with current.
A HV meter of any kind won't draw any current to speak of.
Measuring "plate current" or other stuff from a HV supply is not related to measuring the voltage, at all.
As W1VT pointed out, any DC voltmeter can become a high voltage meter with enough resistance in series with it. Just be careful -- a lot. It's best to connect the test instrument(s) to a HV source while that is still shut OFF, then turn on the source while you, your fingers and all body parts are nowhere near the high voltage.
Also be aware that some resistors-mostly carbon I think- change their value with high voltages. Don't know why.
TOM K8ERV Montrose Colo
Use a high voltage probe that is designed for your meter. Nothing else. I cannot believe that you guys are advocating a string of resistors. What if the guy touched a bare wire lead on one of the resistors closer to the plate cap?
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TOM K8ERV Montrose Colo