The Armstrong Oscillator is named for Edwin Armstrong, its inventor. It is sometimes called a tickler oscillator because feedback is provided using a tickler coil (T in the illustration) and is coupled by magnetically between coil L and coil T. The frequency of oscillation is determined primarily by the tank circuit (L and C in the illustration). In practice, the loading of coil T has some effect on the frequency of operation.

Basic Armstrong Oscillator

This circuit is the basis of the Regenerative Receiver .