DSCN3108
Voltage measurement circuit for panel meter. Input AC (from the tank) is rectified by two UF4004 diodes in series and smoothed with a 47nF 1kV cap. This is divided down with resistors to run the panel meter. Calibration involves applying say 282V dc direct to the smoothing cap, and adjusting the trimpot until the meter reads 200V (rms), since the voltage on the smoothing cap will be the peak voltage of the AC input waveform, less a few diode drops which are negligible.
DSCN3108
Voltage measurement circuit for panel meter. Input AC (from the tank) is rectified by two UF4004 diodes in series and smoothed with a 47nF 1kV cap. This is divided down with resistors to run the panel meter. Calibration involves applying say 282V dc direct to the smoothing cap, and adjusting the trimpot until the meter reads 200V (rms), since the voltage on the smoothing cap will be the peak voltage of the AC input waveform, less a few diode drops which are negligible.