Optical shield (CB20698E)

This circuit was found in American documentation from the 90s. The coupler is the type that uses a photo-Darlington.

Alarm (CB196E)
When the sensor X1 is opened, the relay is energized. When waiting, the current drained is very...
4-Range AC Millivoltmeter (CB25230E)
Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of...
70mA current regulator (CB8821E)
This circuit was found in a 1968’s Motorola documentation. The transistor is from that time. The...