Although it uses a dual-channel FET, which is hard to find today, this circuit was released in a Radio Electronics issue in April 1986. It serves as a signal booster for a wide range of frequencies.
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...