What determines the output frequency of a crystal-controlled oscillator?

The output frequency of a crystal-controlled oscillator is primarily determined by the resonant frequency of the piezoelectric crystal. This frequency is a fundamental characteristic of the crystal, which is designed to vibrate at a specific frequency when an electrical signal is applied.

When voltage is applied to the crystal, it oscillates at its natural resonant frequency due to the piezoelectric effect, which converts electrical energy into mechanical vibrations. The oscillator circuit then amplifies these vibrations, producing a stable output frequency.

The characteristics of the crystal, such as its size, material composition, and cut, directly dictate this resonant frequency. As a result, the stability and accuracy of the oscillator output largely depend on the properties of the crystal itself, making it a crucial component in determining the operational frequency of the oscillator.

In contrast, while capacitors, inductors, and resistors play roles in shaping the behavior of the oscillator circuit, they do not determine the inherent frequency at which the crystal oscillates.