Optical potentiometer (CB22159E)

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

Night Switch (CB12701E)
The circuit shown in the figure activates a small indicator lamp that will start to flash when the...
LM3900 Voltage Controlled Current Source (CB14211E)
The circuit shown is from National Semiconductor's Linear Applications Handbook. The LM3900 is a...
Oscillator for Bias and Erasing Recording Heads (CB1516E )
This circuit was found in a 1976 documentation. It can be used with old tape recording mechanisms for...