This circuit turns off after a time given by capacitor C1. This component can have from 1 to 1,000 uF depending on the desired time. The circuit is from an Electronics Now from June 1995.
Using power transistors of the time, this source was published in Radio Electronics magazine in...
The network formed by resistors and capacitors determines the frequency of this sinusoidal...
The sensor in this circuit is an LDR and the potentiometer serves to control the sensitivity...