Electromechanical Counter (CB21682E)

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

NB FM audio amplifier (CB7462E)
Found in a documentation from the 90s, this circuit limits and amplifies a voice signal in the 800...
Fence Electrifier (CB12895E)
This circuit is from an Argentine publication from the 1970s but can still be assembled with...
Low voltage drop regulator (CB21216E)
This simple LDO, or low voltage drop regulator was found in an Electronic Design from the 90s. The...