This 1969 Electronics World power supply has 5 V to power digital circuits and a 170 V output for Numitron indicator valves used at the time.
This circuit was found in a 1989 publication. The operational amplifier supports equivalents. The...
This humidity sensor indicates the different levels of conduction of the sensors through an LED...
Found in documentation from the 70s, this circuit uses components from that time. Some of these...