Bilateral current source 2 (CB20819E)

We found this circuit in an American publication from the 1980s. Equivalent modern operational amplifiers can be used.

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...