Automatic lighting during power outage

When the mains is normal, the 220V voltage is stepped down by C1, rectified by D1, filtered by C2 and stabilized by D2, and the 6V DC voltage is output to drive J1 to close, so that E obtains the pulsating floating charge current through D3. At this time, LAMP1 is not lit. If there is a power outage, J1 is released, and LAMP starts to work with power supplied by E1. D3 is used to prevent the battery from discharging in reverse after a power outage.