This is the first transistorized circuit published in the Radio Electronics magazine from over 1950. It is a simple audio oscillator that can be used as a signal injector. The transformer provides the feedback. Note that the base is the shell.

This is the first transistorized circuit published in the Radio Electronics magazine from over 1950. It is a simple audio oscillator that can be used as a signal injector. The transformer provides the feedback. Note that the base is the shell.