This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics magazine. The source must be symmetrical. The capacitors can be changed for other frequencies.
This amplifier was found in a 70s documentation. The product gain x bandwidth is 350 MHz. The...
This circuit mimics the trill of a bird. We found it in an American documentation from the 90s. It is...
With the values indicated for this circuit, the lamp will flash 60 times per minute (1 per...