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.

Proximity Detector (CB11566E)
This circuit is from a 1965 Argentine publication (Radio Chassis Television). The original...
Microammeter with the 709 IC (CB24197E)
Using a 709 integrated circuit this circuit was found in the June 1972 issue of Radio Electronics...
Temperature sensor shield (CB5093E)
This circuit was found in an old publication and can be adapted for use with modern...