Anyone had success using analogue/digital HV panel meters?

[FPS]

I've been looking at using one of the analogue HV meters found on Aliexpress/Ebay which are essentially a milliamp meter wired through a high value resistor. So in theory to convert a 100ma meter to 100kV meter you just need to add a 1GOhm resistor in series, same resistor is true for 10ma to 10kV etc. directly convert ma to kV using 1G of resistance.

This should hold true for the digital meters too correct? so this https://www.ebay.com.au/itm/181340921927 200ma digital meter in series with a 1G resistor should read 0-200kV, will this be at all accurate at the low end? if I wanted to differentiate 3kV and 5kV for example.

I'm asking this as I did buy a 50kV meter a while ago, and now that I have a HV probe I can test it. It only reads half the true value.

[TizianoBll]

Yes, they should show the same value. Digital meters usually are much more accurate than analogs.
You shouldn't go over 1-2mA otherwise you'll load your circuit and have heat problems.

I think you got some calculations wrong: 1Gohm @ 200mA is 200MV, not kV (G = 1e9)!
With this setup 1kV/200MV = 0.0005%, way too low for a cheap meter, you would need a 6.5digit laboratory multimeter. A 200mA meter in series with a 1G resistor is not a good solution. A better solution would be to replace the internal low resistance shunt with a higher value one (10, 100... ohms) to get better resolution.


A disadvantage of digital meter is that they are sensitive to interferences (if there's an arc they often reset).

[FPS]

Oh, sorry swap the mA for uA, giving 200uA meter in series with 1G resistor for a 0-200kV meter.

200uA digital meter https://www.ebay.com.au/itm/382508507644 , yes I hadn't thought about the interference problems, but I guess I'll test it anyway. Only the digital meter will fit where I need it. Wondering how ripple will affect a digital meter compared to analogue too, I'm assuming it will require full wave rectification and capacitor.

I've been trying to upload pictures but SnapDrop is down so I cannot get it off my phone. I've been testing a 50kV analogue meter with 500MOhm resistor as bought off Aliexpress. It came with the resistor.

It doesn't work as planned, Attached to a 20kV source (as determined by probe and 20mm spark gap) it reads 10kV. Now if I remove the analogue meter and attach the probe to the end of the resistor it also reads 10kV. So the resistor is halving the voltage :/

[Luca c.]

be careful that digital meters don't go well with high voltage, I once destroyed one because of static electricity at only 30kV through a high voltage resistor because of corona, so if you plan on using them try to have them far away from a possible high voltage electrode that might emit some corona discharge and connect to earth to avoid charge buildup. to avoid ripple try connecting some capacitors across the high-voltage resistor. Maybe the problem with the 50kV is that the resistance is double the expected value, if you have a digital uA meter accurate enough you may be able to estimate the resistance value with around 100v.

[MRMILSTAR]

I would stick with analog meters for HV work. As others have said, digital meters are much more sensitive to interference and can be easily damaged. For several of my projects I use a 25 microamp meter and a 1G ohm HV resistor in series. I can measure up to 25 KV and the numbers on the scale correspond to the voltage.