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| 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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