This circuit is the receiver for the previous transmitter modulated by an audio signal. The transducer is a ceramic capsule, in which case the circuit becomes ideal for telegraphic transmissions.
Found in documentation from the 1980s, this circuit can generate signals in a range that reaches a few...
Found in a 1967 publication by General Electric, this control is intended for motors up to 2 A...
This circuit was found in a 90s Popular Electronics. The circuit uses components from that time,...