Null Indicator (CB21930E)

This bridge was found in a Raytheon transistor manual from the 1960s. The transistors are germanium from the time.

Two Transistor Siren (CB4210E)
This well-known siren configuration using complementary transistors is from a 1980s documentation. The...
Light Beam Operated Relay (CB4956E)
This circuit was found in an old American magazine and could make use of more modern components...
RIAA Preamp (CB1260E)
This circuit is from the Philips integrated circuits manual of 1990. It is intended for magnetic...