This simple emergency lamp circuit uses very components and yet is able to provide some useful service. The shown device is able to switch ON automatically when mains power fails, illuminating all the connected LEDs.As soon as power is restored, the LEDs shut off automatically and the connected starts charging through the built in power supply. The circuit employs a transformerless power supply for initiating the explained automatic actions and also for trickle charging the connected battery.
Parts List
R1 = 220K,
R2 = 10K,
D1, D2, D3 = 1N4007,
Z1 = 15V 1watt, zener diode,
C1 = 105/400V
C2 = 100uF/25V
T1 = 2N2907, or 8550, or BD 140
Z1 = 12V, 1 watt
LEDs = white, high bright type.
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