This circuit makes use of a specific 80's component and was found in an American manual of the time. A matrix keyboard allows you to select one of several music programs.
When the sensor of this circuit is cut for a moment, the second 555 produces a tone for a time...
Using the 723 integrated circuit, this power supply has the voltage determined by R2 and R3, which...
This circuit was found in the ON Semiconductor's Thyristor manual of the 1980s. The high quality...