The power supply for this 1972 circuit must be symmetrical and the BC549 transistors. Care with the layout is important to avoid capturing tinnitus.
The diagram shows a tone control with the LM381 IC. The circuit is from a Radio Electronics from...
This circuit was found in an old European documentation. When R2 is cut off the circuit triggers...
In the figure we show a timer, this simple one with only one of the four gates of integrated...