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.
Unlike white noise, pink noise has a spectrum whose amplitude decreases with frequency. This...
We found this circuit in the April 1992 issue of Radio Electronics magazine. The circuit uses an...
This circuit sends its signals through a wall acting as an FM spy. The circuit is from an...