This good power amplifier, a few tens of watts, is part of an article in the December 1972 Radio Electronics magazine. The power supply must be symmetrical with at least 3 A.
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...