We found this circuit in the September 1994 issue of Electronics Now magazine. The circuit uses off-the-shelf components and is powered by mains power.
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...