This somewhat complex circuit was found in the May 1984 issue of Radio Electronics magazine. The circuit drives a power stage with a triac for loads connected to the power grid.
The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals...