This circuit was obtained in a documentation about old neon lamps. The circuit indicates when a home appliance with thermostat and heating element is on.
This circuit was found in a 1970s General Electric documentation. Transistors are uncommon today....
Found in Ferranti's 1969 documentation, this circuit can be mounted with a modern equivalent...
This circuit beeps when the sensor is triggered by the opening of the freezer door or other...