This circuit for multiple sound inputs was found in a Radio Electronics from January 1992. It consists of a Bargraph connected to a multi-input mixer.
This fast trigger circuit allows the counting of up to 300 pulses per minute. The circuit is from...
This long delay circuit was found in the July 1973 Radio Electronics magazine. The capacitor...
In the figure we show how to use an LM324 as a voltage comparator the reference voltage is...