Found in 1980s Electronic Engineering, this circuit uses common phototransistors as sensors. The circuit is CMOS using an integrated 4011.
This power source was found in documentation from the 1970s. The components are from the time, and...
This simple circuit indicates, through an LED, when the water level of a filter (or other kind of...
This unijunction transistor circuit was found in the Radio Electronics magazine from June 1968. The...