Linear Amplitude Modulator (CB21087E)

Found in an Analog Devices documentation from the 90s, this circuit uses a component of the time, not common nowadays.

TRIAC Shot By Reed Relay 2 (CIR3265E)
We find this simple circuit in an English publication called Electronic Circuit Design no. 3 of...
OR gate LM3900 C (CB19125E)
An OR gate can be implemented with an LM3900 transconductance operational amplifier. The circuit is...
Absolute Value Amplifier CA3140 (CB13841E)
This circuit is from the 1977 RCA Linear Integrated Circuits Manual. The circuit has a...