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.
In the figure we have the shot made by an interrupted light beam using a phototransistor or a...
Using a CA3130 operational amplifier, this circuit from a 1977 documentation can handle low...
This is the receiver for the CB1364E transmitter. Other receivers can be found in this section of...