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.
This small audio amplifier was found in the May 1994 issue of Electronics Now magazine. The power...
The displayed relay operates with an audio signal applied to the input. The transistors can be...
The circuit shown in the figure and uses the diode in the leakage current operation mode. In it,...