This circuit is from Radio Electronics from March 1985. The circuit uses common components at the time and LEDs as indicators. The power supply is 9V.
This circuit is from 1983 documentation. The author shows us an experimental circuit of a siren...
This simple circuit indicates whether at a point in the wiring of a car 12 V is present. The clip...
This oscillator employs a Motorola operational amplifier common in the 70s. We can implement the...