This simple power supply circuit triggers when the light on the LDR reaches the level set on the potentiometer. The circuit is from an Electronics Now from July 1995.
This old slide projector control circuit was found in an 80s Hands On. The circuit uses modern...
In the figure we have a circuit that uses unusual components, being indicated for low frequency...
The sensor of this circuit found in Popular Electronics can be formed by a piece of fabric between two...