This circuit has a visual indication of activation and is suitable for people with hearing impairments. The circuit was found in the March 1974 issue of Radio Electronics magazine.
Found in an old Electronic Design, this circuit provides an output voltage that is the absolute...
Other operational amplifiers can be used in this circuit obtained from the manufacturer's own...
Frequency in this oscillator is controlled by a crystal. Any 1 MHz to 15 MHz can be used. The JFET can...