Found in an old Elektor, this circuit uses two 7-segment displays to indicate the volume of an amplifier. The circuit uses components that are still common today.
The power supply shown in the figure provides voltages between 0 and approximately 15 volts, with...
Another triggered oscillator that we found in the November 1984 Radio Electronics magazine. The...
Found in a 1980s German publication, this circuit tests batteries by type. The circuit is based on a...