Broadband amplifier (CB9179E)

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

Infrared controlled soldering station (CB7021E)
This circuit was found in 80's Popular Electronics. The circuit uses an infrared-sensitive phototransistor...
Charge and Discharge Monitor (CB5408E)
Supplied in a 2005 Linear Technology Application Manual, this circuit monitors the charge and...
Null Detector (CB5071E)
We found this circuit in an American 1980s documentation. Transistors may be general purpose...