This circuit was obtained in a 1964 Electronic Design. Equivalent modern transistors can be used. The circuit requires a 6 V symmetrical power supply.
September 2017 - Mouser Electronics already has the AP431S adjustable regulator from Diodes...
Placed near a telegraphic transmitter (CW) and with a small antenna or pickup, it reproduces the...
This circuit was found in a 1980s documentation. The operational amplifier is of a common type at the...