This circuit was obtained from an Electronics Now from the 90's. It generates the dial signal and the ring tone, serving for testing as well as for demonstrations.
This circuit was found in the August 1987 issue of Radio Electronics magazine. It was implemented with...
This circuit, which can act as a shield, was found in a 90’s Radio Electronics. It enables a power supply...
This simple circuit uses a zener diode and two LEDs to indicate whether the voltage of a power grid...