On Sun, Mar 23, 2025 at 02:49 PM, Roy J. Tellason, Sr. wrote:
Somewhere back there I bought a Polaris branded HV probe, a big long thing with a pointy bit on one end, a wire with a clip on the other to ground it, and a meter.
The advantage of an electrostatic voltmeter is there is no load on the power source after the capacitor charges, for high voltage power supplies for things like nite scopes (starlight scopes), these power supplies can't deliver enough current for a 50uA meter such as in the Polaris to get a valid reading. Plus the 50uA load might be enough to damage the power supply.
The spec sheet warns against measuring the voltage, instead they say to use a night scope tube to verify power supply operation.
At a guess, I'd say these power supplies can provide a few uA of current.
Both of my night scope power supplies have auto-shutdown. If you touch the high voltage you'll feel a bit of a bite then nothing. These power supplies are designed to be as efficient as practical to maximize battery life.?
From a military perspective, it'd really be a bad thing for the battery in your night vision scope to die while you are either on overwatch or an active patrol....
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Being paranoid, I'd try to change the battery every night before going out. But some night scopes use expensive, odd, batteries. Both of mine use 4 AA and will run about 18 hours.?
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This is the battery used in the first deployed US Starlight Scope
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The PVS-1 could use the BA-3100/U (alkaline)? or BA-1100/U (Mercury) batteries.
I made some adaptors that used 4 "AA" because the proper batteries were "unobtanium".
[The PVS-1 sucked bilge water compared to any 2nd or later gear.]
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Electrostatic voltmeters are old technology and I don't think any company is still manufacturing them.
In a world with 12V, 9V, 6V, 5V, and 3.3V there isn't much need for electrostatic voltmeters.
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