This 20W amplifier was found in 283 circuits from the 90s. The MOSFET admits equivalents. The power supply must be dual, and the transistors must be mounted on good heat sinks.
This Colpitts oscillator with JFET has the amplitude of the signals stabilized by a diode. The...
This circuit is from European 90s documentation. The integrated circuit used is not very common...
This circuit of an old publication makes use of SCRs that admit modern equivalents. The frequency...