The working principle of crystal oscillators

Crystal oscillator is a common electronic component used to generate stable clock or frequency signals. The working principle of crystal oscillators is mainly based on the piezoelectric effect and mechanical resonance phenomenon of crystals.

A crystal oscillator typically consists of a crystal chip and a circuit connected to it. Crystal chips are made of quartz or ceramic materials and have piezoelectric effects. When voltage or mechanical stress is applied to a crystal chip, the chip will generate a buildup of charges, which is called the piezoelectric effect. The size and shape of a crystal chip determine its resonant frequency.

Crystal oscillator circuits are generally composed of crystal chips, capacitors, and inductors. The crystal chip is connected to the circuit to form a resonant circuit. When a voltage is applied to the circuit, the crystal begins to vibrate and generates a stable frequency. This frequency is determined by the physical properties of the crystal chip, typically ranging from several thousand hertz to several hundred megahertz.

The following is a detailed explanation of the working principle of crystal oscillators:

1. Piezoelectric effect: Quartz crystals have the characteristic of generating charges when subjected to mechanical pressure, which is called the piezoelectric effect. On the contrary, when charges are applied to the crystal, it will generate mechanical vibration.

2. Mechanical resonance: Quartz crystals in crystal oscillators are cut into specific shapes and sizes to vibrate at their natural frequencies. When the frequency of the applied alternating voltage matches the natural frequency of the crystal, the crystal enters a resonant state, the vibration amplitude increases, and a stable electrical signal is generated.

3. Equivalent circuit: The electrical characteristics of a crystal oscillator can be described through its equivalent circuit, which includes components such as resistors, capacitors, and inductors. The values of these components are related to the physical properties of the crystal oscillator, such as the cutting method, geometric shape, and size of the crystal.

4. Parameter influence: The performance of crystal oscillators is influenced by various parameters, including resonant resistance, load capacitance, and temperature stability. These parameters determine the frequency stability and applicable environment of the crystal oscillator.

The working principle of crystal oscillators is based on the physical properties of crystals and the resonance principle of circuits. Its stability and accuracy make it an indispensable component in electronic devices. By designing the parameters of the crystal oscillator reasonably, it can meet the needs of different devices for clock signals or frequency signals.