Found in a 1968 Novel Electronics Circuit, this circuit compares two light intensities using common LDRs as sensors. Transistors can be modern PNP equivalents.
When a voice signal enters this circuit, the volume of the music being played automatically...
In the figure we have a circuit used in stair generators with the purpose of providing constant...
This article was obtained in a French magazine Nouvelle Electronique from 1994. It can be easily...