I have variac (Uin=230V, Uout=0-250V, Imax=5A), where I would like to measure voltage on output on a digital voltmeter. Since I have problems finding digital AC voltmeter 0-300VAC (most of them measure only from ~70V up, but I would prefer form 0V up), I was thinking of measuring voltage with DC voltmeter (these are easy to find to measure 0-300VDC with external power supply of 5-12VDC). What I would like to do is this:
Gretz is used because of DC voltmeter, where I used cap. to smooth the halfperiods into something more likely DC voltage, while resistor is there to discharge (and for faster changes). Voltage divider is there to divide the voltage, for when it's 324V (230V*1.41) to show on DC voltmeter 230V DC.
Is this a correct way to solve the problem?