This oscillator uses a small IF transformer taken from an old transistor radio. FET admits equivalents. The circuit can be used to calibrate radios.
The S-meter is signal strength meter, coupled to telecommunications receivers to indicate the...
This circuit is suggested by Motorola, making it possible to use an optical coupler of type 4N26...
Dynamic analyzer is another name given to a signal follower or signal chaser. This circuit is from...