This traditional dimmer configuration for incandescent lamps and heating elements was found in an RCA transistor manual. SCR can be a more modern equivalent like TIC106, depending on the power grid.
A ring and pendulum of stripped wires form the sensor for this alarm. Once triggered, to reset, you...
This radiation detector was found in an American publication from the 60's. The circuit uses a...
In the figure we have a simple timer with the 555 feeding a relay directly. The circuit is from...