摘要：随着电子科学技术飞速发展，电子测量变得越来越普遍，同时对测量的精度和功能的要求也越来越高，其中以电容的测量最为突出。而且随着电子技术的发展，更是经常需要测量高精度的电容，所以数字电容表就成为一种必不可少的测量仪器。92678

本次论文设计的基于proteus的数字电容表，其主要构成采用的是单片机AT89C52、六位LED数码管及电容充放电电路。根据电容充放电原理和单片机的功能特点，并结合一个普通的电压比较器，用单片机内部的定时系统测量电容充电到电压值为0。632E+（E为电压比较器反相端接的定值电压，此时电压比较器会输出一个高电平，也即是单片机停止计时信号）时所用的时间，通过测量电容的充电时间计算出电容值，再把电容值的大小通过六位LED显示。设计中C52单片机通过软件C语言编程，实现了四位nf级电容的测量。

毕业论文关键词：proteus,单片机，数字电容表，LED数码管

Abstract:   With the rapid development of Electronic Science and technology, electronic measurement is becoming more and more common, and the requirements of measurement accuracy and function are higher and higher, among which capacitance measurement is the most prominent。 Moreover, with the development of electronic technology, it is often necessary to measure high-precision capacitance, so digital capacitor meter has become an indispensable measuring instrument。

  The digital capacitor meter based on Proteus designed in this paper is mainly composed of single chip microcomputer AT89C52, six bit LED digital tube and capacitor charge discharge circuit。 According to the features of capacitor charging and discharging principle and microcontroller, combined with a common voltage comparator for measuring capacitance timing system of single-chip internal charge to voltage value is 0。632E+ (E is the reverse voltage comparator termination constant voltage, the voltage comparator outputs a high level, which is MCU stop timing signal) when the time used by the charging time of measuring the capacitance of the calculated capacitance, the capacitance by six LED display。 In the design, C52 single chip microcomputer through software C language programming, realized four bit NF level capacitance measurement。

Keywords: proteus, single-chip, digital capacitance meter, LED

目  录

1绪论 4

1。1数字电容表的设计概况 4

1。2设计单元选择依据 5

1。3设计的方法和意义 5

2。电容表制作的方案选择 6

2。1 测量电路方案 6

2。2显示方案 7

2。3方案选取 8

2。4系统框图 8

3。硬件电路原件概述 9

3。1 AT89C52单片机 9

3。2电压比较器 12

3。3LED数码管 12

4。 硬件电路设计实现 12

4。1硬件电路组成部分和设计单元的实现 12

4。2 单片机电路 13

4。3电容充电电路 13

4。4  LED数码管电路 15

5。软件设计 15

5。1软件流程图