This interesting benchtop circuit was found in the May 1977 issue of Radio Electronics magazine. The circuit has frequency adjustment, and the waveform selected by a switch.
The quiescent current of this alarm is in the order of microamps and the same is true for the...
This circuit is from a 2005 Linear Technology publication. It converts current into load sensing...
This circuit can operate in a 100 dB range with signals of up to 100 MHz frequencies. Similar...