I recently purchased 2 little voltmeters they look like the sort that would go in a control or instrument panel they are connected with just 2 wires which provide the operating supply ( they light up green and red) however the green one states it will work between 20and 500 volts and the red one between 60 and 480 volts. When they are both on the green one indicates normally around 241 volts the red one shows 235 volts why the discrepancy I know it's not much but makes you wonder if one of them is lying. Secondly I've noticed that the green one tracks voltage changes faster than the red one and that a few times the green one jumps down to 238 then up to 241 multiple times while the red one stays the same and I think can see a slight flicker in my filament lamps when this is happening incidentally both meters are connected to the same plug a 2 pin 5 amp one
Can I ask what's a TH lamp? I will do some tests with my variac and see what results I get if I can get a TH lamp it wil be interesting to know if my mains has harmonics in it I have come to the overall conclusion is that because my 2 new meters and my multimeter all show figures within about 5 volts of each other I can safely say my supply is around 240 volts which is where it's supposed to be so that's good. Also the analogy with cars average and peak speeds is also helpful in that I now fully understand that digital meters don't continually read the voltage but just look at certain points in the cycle it's all making sense now. I tried my vtvm which I bought at the same radio rally as the digital meters and guess what? it don't work it lights up and the needle moves when you adjust the zeroing knob but that's all it does on both AC and DC volts so if I can't fix it il re sell it next year
Can I ask what's a TH lamp? I will do some tests with my variac and see what results I get if I can get a TH lamp it wil be interesting to know if my mains has harmonics in it I have come to the overall conclusion is that because my 2 new meters and my multimeter all show figures within about 5 volts of each other I can safely say my supply is around 240 volts which is where it's supposed to be so that's good. Also the analogy with cars average and peak speeds is also helpful in that I now fully understand that digital meters don't continually read the voltage but just look at certain points in the cycle it's all making sense now. I tried my vtvm which I bought at the same radio rally as the digital meters and guess what? it don't work it lights up and the needle moves when you adjust the zeroing knob but that's all it does on both AC and DC volts so if I can't fix it il re sell it next year
