Products > Test Equipment
New UNI-T UT892 2000V AC/DC High Voltage Multimeter
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Fungus:
What's the "live" socket for?

It appears to go through the range switch after the PTC. Seems dodgy to me...what's the clearances on the other side of the PCB?
Fungus:

--- Quote from: Kleinstein on August 29, 2022, 11:16:53 am ---I would not use it for higher mains voltage or CAT3 use, but it could still be a good meter for the few cases where you have 1000-2000 V with a limited current

--- End quote ---

I'd want a much higher input impedance for that.

The small, high voltage supplies I've used tend to have very limited current. Even 20MOhm could be enough load to give an incorrect reading.
Gyro:

--- Quote from: Fungus on September 08, 2022, 05:09:21 pm ---
--- Quote from: Gyro on September 08, 2022, 04:55:22 pm ---- I wonder what the voltage rating of that PTC is- although they have excluded the 2kV jack from the cat rating.

--- End quote ---

How many volts would you need to apply to heat up a PTC in series with a 20MOhm resistor?

--- End quote ---

Ha, good point, the PTC isn't there for to protect the voltage function on normal meters is it!
PartialDischarge:

--- Quote from: Fungus on September 08, 2022, 05:20:43 pm ---
--- Quote from: Kleinstein on August 29, 2022, 11:16:53 am ---I would not use it for higher mains voltage or CAT3 use, but it could still be a good meter for the few cases where you have 1000-2000 V with a limited current

--- End quote ---

I'd want a much higher input impedance for that.

--- End quote ---

CAT rating does not mean higher input impedance, it means higher clearance/creepage and higher power rating of passives.


I think the meter is fine, without current measurements which I seldom use it simplifies the board, protections and price of the meter. Also it has a 9V battery which will probably last longer than 2xAA.
PartialDischarge:
So I decided to modify the meter, since I don't know how good those 2.5M resistors are, I replaced them with 2.4M ones that I have. Also I removed the PTC and put there the rest of the resistance minus a bit to compensate for the low 0.2% reading. Now it is measuring +-1V.


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