High voltage measurement circuit

The high-voltage power supply circuit for measurement is shown in the figure. VD1, VD2. C] and C3 form a voltage doubler rectifier circuit; VD3, Vly, G, and C
form another half-wave voltage doubler rectifier circuit with opposite polarity. After the two circuits are combined, they can output +275V, -550v, and -1100v high voltage .
    Since an isolation transformer is not used, for safety reasons, a phase line indicator that can be touched by hand is set up so that the end connected to the switch is always a
phase line. When using it, first turn on the power and touch the copper sheet with your hand. If the neon light is on, it can be used. R2 is the current-limiting resistor that protects the meter.
The full-scale current of the meter is O.lmA. It can also be replaced by the current range of a multimeter.
    The diode withstand voltage should be greater than 600V. No current requirement. Capacitors Ci and C2 have a capacity of 0.22vF and a withstand voltage of 250V. Capacitors C3 and C4 have a capacity
of 0.22vF and a withstand voltage of 630V. Yes for sookfl, R2 is 750kfi.