We found this circuit in documentation from the 1980s. The transformer is of the low voltage type with a 1: 3 turn ratio and the transistors can be of general-purpose types.
We obtained this circuit in a 1987 publication. It is the traditional French siren configuration with two...
We found this circuit in April 1979 Radio Electronics magazine. The circuit is based on the 555...
This simple circuit helps to save incandescent lamps by leaving their filament slightly heated and thus...