This ultra-low noise amplifier and simple power supply was found in Analog Devices documentation from the 90's. The circuit can be implemented with modern equivalent components.
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...