Light operated switch in lamp-holder - is controlled by thyristor and photoresistor at end of optical fibre exposed to ambient light

摘要

The holder (1) has an Edison screw fitting (2) for a socket and an internal socket (3) into which the lamp is screwed. The end of an optical fibre (5) is inserted through a hole (4) in the holder (1). Ambient light from the remote end (41) of the fibre passes through an adjustable shutter (9) and a fixed shutter (8) to a photo resistor (7) connected to a thyristor switching circuit. The remote end of the fibre can be fixed to the inside of a window with a suction cap and the adjustable shutter aperture varied (10) so that the lamp comes on when the outside light level falls, e.g. at dusk, and goes off at dawn.