Optical potentiometer (CB22159E)

This voltage-controlled potentiometer using an LDR was found in an English documentation. LDR is common and LED of any type.

1600 m Line Receiver (CB13060E)
In the figure we have a circuit for line receiver (twisted pair) with the possibility of...
Automatic Level Control (CB25899E)
This circuit appeared in the November 1995 issue of Electronics Now magazine. The circuit uses...
Locked Touch Seitch (CB10232E)
This circuit was found in a 1987 edition of the United States' Hands On Electronics magazine. The...