This circuit was obtained in an American documentation from the 80's. The transistors can be equivalent to those indicated and the crystal can reach a few tens of megahertz.
This interesting touch dimmer was obtained in a 1993 publication, basically consisting of a...
This circuit was found in an Electronic Design from the 90s. The circuit uses a type J...
This amplifier was published in Radio Electronics magazine in September 1959. The 8-transistor circuit...