Found in Popular Electronics from the 90s, this circuit uses a reed switch on the rails as a sensor. Instead of lamps, in a modern version, LEDs can be used.
The presented circuit was found in a 90’s Electronic Engineering. The circuit is based on CMOS...
We find the original version of this circuit in an English publication (1986). It is a...
Found in a 1990s Electronics Now, this circuit uses a period-specific integrated circuit that...