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.
The circuit shown in the figure can be used to detect the operation of infrared sources whose...
This circuit is from a factory manual from the 80s. The circuit can be implemented with more...
This circuit for the logic control of the 555 in a power supply was found in the October 1989...