This circuit was found in 80's telecom documentation. Its purpose is to control a microphone in the process of transmitting voice and Morse signals.
This oscillator produces a rectangular signal in the range of 100 Hz to 1 kHz, but by changing the...
This circuit was originally designed for the alarm of the CB17984E, but it also serves for any...
We found this version of the siren that makes the American police siren sound in a 1980...