Found in a European magazine from the 90s, this circuit emits beeps that are several seconds apart to indicate that a device is on. The transducer is a ceramic or crystal capsule.
This circuit was obtained in 1974. It serves to indicate the tuning of stations on a common...
This circuit with Norton operation is from an article in Radio Electronics magazine. The gain is...
In the figure we have one of the many ways to program the counting of a 4017. The circuit uses...