This sophisticated audio generator with digital display was found in the March 1984 issue of Radio Electronics magazine. The circuit includes a power supply with various voltages.
With the coded activation of the relays, it is possible to control which of the 16 outputs...
The integrated circuit used in this application is not very common. Transistors and resistors...
This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are...