This circuit is part of an article published in the March 1990 issue of Radio Electronics magazine. The sensor consists of a grid-shaped electrode shown in the figure.
Found in a 1963 documentation, this circuit employs germanium transistors of the time. Transformer and...
In the figure we have a way of receiving ultrasonic signals of a single frequency using a PLL 567....
This traditional circuit generates a 200 Hz sinusoidal signal. The frequency depends on the...