This circuit can use almost any operating system and has a high input impedance. The power supply must be symmetrical. The circuit was obtained in documentation from the 1980s.
With the circuit shown in the figure we have a frequency modulation which is produced by a...
This is a circuit found in a 1970's Radio Electronics. The circuit works with virtually any triac...
This circuit was found in a 1970s RCA publication. Transistors support modern equivalent types....