This amplifier was found in a 1970s documentation. Darlington transistors can be replaced for modern equivalents of at least 80 V x 2 A, equipped with good heat sinks.
This circuit is quite simple to assemble, having been found in a traditional American publication. The...
This rectangular oscillator produces signals of two frequencies, one double the other. The circuit is...
This oscillator can generate signals up to about 10 MHz, depending on the crystal used. The...