This circuit was found in General Electric documentation from 1968. The circuit uses triac from the time as well as transistors that can be replaced by modern equivalents.
Using in operational amplifier is possible to increase the dissipation power of a zener. This...
In the figure we show a configuration for a crystal-controlled overtone oscillator using a...
The circuit is from the MC1539 manual, an operational one close to the 741. The transistor admits...