This circuit, found in 2002 documentation, triggers LEDs when a phone call is received. The LEDs will flash alternately in these conditions. Common LEDs are used in this circuit.
Using neon lamps, this regulator was found in a1969’s documentation. The lamps are types available...
In the figure we have the power supply for the 8 W amplifier in the previous circuit. The circuit...
We found this circuit in the April 1988 issue of Radio Electronics magazine. The circuit can be...