Electronic power-on delay

The power supply for the delay circuit is derived directly from the mains by a bridge rectifier; D1-D4. The rectifier must be able to handle a current of up to 1 A. Für safety reasons, resistor R1 ensures that capacitor C1 is discharged rapidly when the mains is switched off. The resistor should, therefore, be rated at 250 V a.e. or 400 V d.c.