Based on the BA1404 integrated circuit, this circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is short range, but a power amplifier stage can be used.
The basis of this circuit is the 723, an old integrated circuit not easier to find these days. The...
This circuit was found in a May 1981 Radio Electronics magazine article. The circuit is offset...
The circuit presented was found in a Japanese magazine in 1973. The circuit uses transistors of...