Electromechanical Counter (CB21682E)

This photoelectric circuit from a 1960 publication uses a 6.3 V electromechanical counter, common at the time.

Passage Alarm (CB24151E)
This sensitive passage alarm was found in the August 1971 Radio Electronics magazine. The light...
1 kHz Band Pass Filter (CB19689E)
This filter has the components calculated for the frequency of 1 kHz but can be changed. The input...
Simple H-bridge (CB23725E)
The direction of rotation of the M motor can be controlled by an Arduino or another...