Introduction to RC oscillator and crystal oscillator

RC Introduction to oscillator and crystal oscillator

     oscillator （oscillator） It is an energy exchange device —— Convert direct current energy into alternating current energy with a certain frequency . Here are two common oscillators ：RC Oscillator and crystal oscillator .

RC oscillator （Resistance & Capacitance）
     In the frequency selection part of the oscillation circuit, only resistors can be used （resistance） And capacitance （capacitance） constitute . This kind of oscillator consisting only of resistors and capacitors is called RC oscillator .
advantage ：
     Lower cost of implementation , After all, it is a resistor capacitor .
shortcoming ：
     Because of the accuracy problem of resistance and capacitance RC The oscillation frequency of the oscillator will have errors , At the same time, it is subject to temperature 、 The effect of humidity . This is related to the process of components .

Crystal oscillator （ Crystal oscillator ）
     As long as the alternating voltage is applied at the crystal plate level , The chip will produce mechanical deformation and vibration , This phenomenon is called inverse piezoelectric effect . When the frequency of the applied voltage is equal to the natural frequency of the crystal resonator , Piezoelectric resonance will occur , Thus, the amplitude of mechanical deformation suddenly increases .
advantage ：
     generally speaking , The oscillation frequency of the crystal oscillator is relatively stable .
shortcoming ：
     The price is a little higher , There are usually two crystal oscillators connected 15-33pF Starting capacitance .