This siren configuration found in a documentation from the 1980s can also be seen in many of our projects and in this circuit bank. Transistors are common, but Q2 can be of power for a higher voltage supply.
We found this circuit in a year 2000 documentation. It must be powered by a voltage of 5 V as it...
This circuit was found in the February 1990 issue of Radio Electronics magazine. The circuit uses...
Voltage comparators, such as those in the LM139/239/339 series, consist of devices that can be...