Optical sensor for PC (CB20548E)

This circuit was found in a PC documentation from 1996. It can be used as a shield with modern microcontrollers.

Injector and Continuity Tester (CB4452E)
This useful instrument has dual function, operating both as signal injector and continuity tester. The...
3 to 6 V x 3A power supply (CB19306E)
This 3 A adjustable source uses the LM350 integrated circuit, which must have a good heat...
Flashlight PWM Control (CB13765E)
The transistor for this flashlight brightness control may be the BD135. The circuit is from 1978...