Found in a 1980s documentation, this circuit uses transistors from that time. Modern equivalents can be used. The alarm is a piezoelectric buzzer with na included oscillator.
This traditional oscillator circuit that can be found elsewhere in this section uses general...
This circuit can be used for signaling a panel with a common incandescent lamp. The lamp will...
This digital indicator circuit was found in the June 1988 issue of Radio Electronics magazine. The circuit...