Hartley Oscillator Calculator

A Hartley oscillator is a type of LC oscillator that uses two inductors (L1 and L2) and one capacitor to generate sinusoidal oscillations. It's commonly used in RF applications due to its simplicity and stable frequency output. See also our PLL PFD Frequency Calculator.

Mutual inductance between the two coils adds to the total inductance in the circuit. The total inductance is L1 + L2 + 2M, where M is the mutual inductance. Higher mutual inductance decreases the oscillation frequency.

Hartley oscillators use two inductors and one capacitor, while Colpitts oscillators use one inductor and two capacitors. Hartley oscillators are easier to tune but may have higher harmonic distortion compared to Colpitts oscillators.

The Q-factor of the inductors and capacitor, the coupling between coils, and the active device characteristics all affect oscillation quality. Higher Q components produce more stable oscillations with lower phase noise. You might also find our Relaxation Oscillator Calculator useful.

Yes, Hartley oscillators work well at radio frequencies (RF) and are commonly used in transmitters and signal generators. However, parasitic capacitances become more significant at very high frequencies.

Choose values based on your desired frequency using the formula f = 1/(2π√(LtotalC)). Consider the Q-factor, availability of components, and the tuning range required for your application.

If there's no mutual inductance (M=0), the total inductance becomes simply L1 + L2. This represents the case where the inductors are positioned to minimize coupling between them.

Real-world factors like parasitic capacitances, inductor self-resonance, component tolerances, and loading effects from the active circuitry can cause deviations from the calculated ideal frequency.