基于AT89C51单片机和555芯片构成的多谐振荡电路设计一电容测量电路，这种测量方法主要是通过一块555芯片来测量电容大小。让555芯片工作在直接反馈无稳态的状态下，555芯片输出一定频率的方波，其频率的大小跟被测量的电容之间的关系是：f=0.772/(R*Cx) ，固定R的大小，其公式就可以写为：f=k/Cx，只要能够测量出555芯片输出的频率，就可以计算出测量的电容。计算频率的方法可以利用单片机的计数器T0和中断INT0配合使用来进行测量。

文件内含有proteus工程及keil工程建立，详细步骤。-A capacitance measurement circuit constitute multivibrator circuit based the AT89C51 microcontroller 555 chip design, this measurement method to measure the size of the capacitor through a 555 chip. 555 chip work under the direct feedback astable state, the relationship between the 555 chip output of a certain frequency, square wave, the frequency of the size of the measured capacitance is: f = 0.772/(R* Cx), fixed R the size, the formula can be written as: F = k/Cx, as long as it can measure the frequency of the 555 chip output, can be calculated a measured capacitance. Ways to calculate the frequency used in conjunction with use of single-chip counter the T0 and interrupt INT0 to be measured.