Indicated for calibrating digital instruments and circuits, this circuit was found in the June 1982 issue of Radio Electronics magazine. The circuit is based on components that are still available.
The oscillator in figure 1 can be used in alarm, call or warning systems, producing a sound of...
This circuit is from a 1973 documentation. In it we have the way of using a FET as an input of...
This circuit is for traditional old-style telephone lines found in an American 1980s...