This is one of the many possible siren configurations for the 555 integrated circuit. We found it in the October 1992 Radio Electronics magazine. It has a power stage.
This circuit has both frequency and duty cycle control. We found it in the October 1992 Radio...
This power supply is indicated for the supply of not very powerful car radios of the AM and FM...
In the absence of a modulation signal, the carrier of this simple short-range transmitter is cut...