(论文 字数:16509页数:40)摘要:本文介绍了一种较为新颖和实用的数字式电容测量仪。它由测试电路和显示电路两部分组成。在测试电路中,第一个555定时器做多谐振电路,它通过电容配合电阻冲放电产生一系方波脉冲。第二个555定时器组成单稳态触发器,它利用被测电容Cx的充放电过程去调制一个频率和占空比均固定的脉冲波形,使其占空比q与C 成正比,显然经过衰减电路取出合适的脉宽的直流电压Vo。然后由MC14433通过A/D转换,同时由MC1403提供合适的基准电压,再通过七段锁存译码驱动器CD4511译码和MC1413的达林顿反向驱动从LED显示器上读出电容。 [关键词] 555定时器,MC14433,MC1413,CD4511, MC1403,A/D转换 HIGH PRECISION FIGURE INSTRUMENT OF THE CAPACITANCE SURVEYING Summary :This text introduced a kind of more novel measure the equipment with the practical arithmetic figure type electric capacity.It from test electric circuit with show the electric circuit two parts constitute.In test electric circuit, the first 555 settle the machine does many flaps the electric circuit, it pass the electric capacity the match the electric resistance washes to turn on electricity to produce a department square a pulse.A charge for 555 settling machine constituting single steady 态 triggering machine, it making use of drive measuring electric capacity Cx turns on electricity the process makes a frequency with account for pulse a form of empty ratio all fix, making its occupy empty ratio q and C direct proportion, reduce through reduces obviously the electric circuit take out the wide direct current in fit vein electric voltage Vo.Then be passed by MC14433 the A/ D convert, being provided by MC1403 at the same time fit basis electric voltage, pass seven more locks saves to translate the code drives the machine CD4511 translates the code to reach the wood with the MC1413 an anti face to drive to read the electric capacity from the display of LED. 目 录 |
数字式电容测量仪的设计
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