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.
We find this circuit in an Electronic Design of the 90s. The used integrated circuit admits...
This shield can be used both to interface TTL circuits and microcontrollers. The resistor in...
This circuit was obtained from an old American documentation having a limited adjustment range....