This well-known circuit version of the siren was obtained in a Colectro Handbook from the 70s. The transistors are of general use, with Q2 being a BD136 for greater power with power from 6 to 12 V.
This SCR circuit can operate on frequencies from 1 to 20 kHz. We found it in an American...
This automotive arrow was found in Motorola's 1990 Linear Databook. The circuit is for lamps, and...
The figure shows how to use a CMOS amplifier as a crystal-controlled oscillator. The circuit is...