This circuit mimics the trill of a bird. We found it in an American documentation from the 90s. It is based on the LM3909 integrated circuits.
The purpose of this PLL circuit that we found in the November 1986 Radio Electronics magazine is...
This circuit is intended for detecting 3 levels power grid voltage, and it can be adapted to...
This circuit, which provides a power of up to 3.5 W, can be supplied with voltages from 9 to 14 V....