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.
Found in Popular Electronics from the 90s, this circuit uses a reed switch on the rails as a...
This low input impedance amplifier stage was found in a 1963 documentation. The circuit employs a...
This 2003 circuit uses two types of sensors: by reed-switch and by infrared. If the magnetic...