This circuit was found in a 1980s documentation. The diodes may be general purpose diodes such as 1N34 or 1N60 and the indicator may be the lowest current range of a multimeter.
This oscillator with base current drop can be used like the well-known grid-dip meters, but which...
This circuit is intended to maintain constant current in a heating element. This element must have...
This circuit was suggested by Philips in 1967 documentation. The circuit receives modulated light and has...