Obtained in a 1968 Electronics World, this circuit uses transistors from the time and the sensor is a common LDR. The component values are for scales from 0.01 to 100 foot-candle.
This circuit has been removed from the component's datasheet. In it we have a monostable or...
This light-controlled circuit uses a 6 V or 12 V relay depending on the supply. The transistor can be the...
In the figure a circuit that is the basic application of NE567 for the detection of a tone applied to...