Broadband amplifier (CB9179E)

Found in an old Popular Electronics, this circuit has a gain of 20 dB. The integrated circuit is uncommon today.

Photoelectric Relay (CB18048E)
The circuit presented is from a 2006 documentation. It can turn a set of lamps on or off when...
10 kHz Variable Q filter (CB13585E)
This second-order filter was found in a 1978 publication and can use common operational amplifiers like...
Guitar tone control (CB9515E)
This simple tone control using two transistors was found in an Electronics Today International of the 90s....