This is an interesting configuration of the LM317 voltage regulator found in an EDN from the 90s. The circuit uses an optical coupler and is intended to supply constant current to a sensor resistor.
The existence of field effect transistors at the input of the integrated circuit (operational...
This circuit generates a siren sound. It was found in the April 1969 Radio Electronics magazine. The...
Suggested by Siliconix in documentation from the 90s, this circuit can present gains of digitally...