With this circuit it is possible to control the intensity of a signal digitally. The circuit is from Radio Electronics from February 1981. The power supply must be 18 V.
This circuit uses a JFET CA3140 operational amplifier to convert a low frequency sinusoidal signal...
This commercial radio for the AM band was sold in Japan in the 1960s. The circuit has an IF of 455...
In the figure we have a simple way to produce tone in a piezoelectric transducer. The frequency depends...