Hartley oscillator

The Hartley Oscillator is an LC oscillator that derives its feedback from magnetically coupled energy in a tapped coil. Hartley oscillator are inductively coupled variable frequency oscillators.

Hartley oscillators may be series or shunt fed.

Structure:

One centre tapped inductor.

One tuning capacitor.

Advantages:

Frequency simply varied by capacity net value in the tank circuit.

Output amplitude remains constant (over the frequency range).

Feedback ratio of inductor 1 to inductor 2 remains constant.

Disadvantages:

Harmonic content rich.

Not suitable for a pure sine wave.

See also: Colpitts oscillator | Clapp oscillator | Vackar oscillator | Armstrong oscillator

External links, references, resources

• Integrated Publishing's Hartley oscillator