Found in an April 1977 Radio Electronics issue, this circuit uses the well-known XR2206. The C1 values for the various frequency bands are given next to the diagram.
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...