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 circuit divides the grid 60 Hz frequency to obtain 20 Hz to drive mechanical watches used at...
This 80's circuit can be implemented with modern equivalent FETs with lower on resistance. The...
This circuit was obtained in a 1964 Electronic Design. Equivalent modern transistors can be used....