This sophisticated circuit with two LF411 operational amplifiers appeared in the November 1984 issue of Radio Electronics magazine. The circuit uses a Mallory buzzer as an indicator.
The circuit shown, with the printed circuit board, was found in an article in the June 1990 issue...
This circuit was obtained from a Radio Electronics issue from January 1989. The indicator is a...
This transmission shield was found in National Semiconductor documentation from the 1980s. Its...