Stereo FM Transmitter (CB8459E)

This circuit was found in a 90s Radio Electronics. The FM encoder or multiplexer is an uncommon component today.

Temperature sensor shield (CB5093E)
This circuit was found in an old publication and can be adapted for use with modern...
Servo Test (CB11388E)
The circuit presented generates pulses at regular intervals with the duration controlled by a...
Volume Expander (CB19809E)
The LS150 is an uncommon high-performance operational amplifier today. The circuit is from old...