Battery-powered night light

Battery-powered night light

This circuit can be used as a nightlight when a wall power outlet is unavailable for plugging in a small, continuously running neon lamp. To ensure minimal battery consumption, a single 1.5V battery and a simple voltage doubler drive a pulsed, ultra-bright LED: current consumption is less than 500 microamps. An optional photoresistor will shut off the circuit when illuminated by daylight or indoor lighting, allowing for further current savings. The device runs continuously for approximately 3 months on standard AA batteries or approximately 6 months on alkaline batteries, but with the addition of the photoresistor circuit, the runtime will double or very likely triple.