Electromechanical Counter (CB21682E)

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

Temperature compensator for VFO (CB8096E)
This circuit was found in a Popular Electronics from the 90s. The circuit has temperature...
Transmitter via power network (CB9574E)
Found in old American documentation, this receiver transmits signals via the power grid. We can...
Precision High Voltage Regulator (CB5878E)
This circuit is from the LM317's own manual obtained from an old documentation. The IC should be...