This circuit is used to detect PLL signals from the 4046 IC. The circuit is from an Electronics Now from October 1994. The indication is made through LEDs.
These circuits use loads of 50 ohms to allow the use of a voltmeter in evaluating the output of a...
This siren was found in a 1980s documentation. The circuit makes use of very old operational that were...
This shield circuit for PC was found in an English documentation from 1996. The current of the...