In the figure we have a way of receiving ultrasonic signals of a single frequency using a PLL 567. The circuit is from Radio Electronics from November 1985.
This General Electric circuit was published in 1970. The LED is infrared and the voltage according...
This circuit was found in the October 1989 issue of Radio Electronics magazine. It drives an...
The transistor can be a modern equivalent and the transformer is the type of output found on an...