Abstract
The basic working principle of digital voltmeter is an analog signal by A/D
conversion circuit to be measured is converted into digital signal, through the
corresponding conversion will test a voltmeter results displayed in digital form.
Compared with the general analog voltage meter, digital voltage meter has the
advantages of high precision, accurate measurement, visual reading, convenient use
etc..
With the development of electronic technology, electronic measuring a large
number of electronic workers must master the means, the measurement accuracy and
functional requirements are increasingly high, while the voltage measurement is very
prominent, because the voltage measurement is most common. This paper introduces
a kind of voltage measurement circuit based on AT89C51 mcu. The circuit uses the
high precision, the double integral A/D conversion circuit, the measuring range is
0-+5 DC volts, the use of LED digital tube display. The paper briefly introduced the
pins and pin function, ADC0808 function and the principle of double integral circuit
is introduced, 74LS373 chip, describes the focus of design ideas for a high precision
digital voltage meter, analyzed the soft, the hardware circuit of the working principle,
design and debugging process, finally has given the detailed test data and analysis.
Keywords: digital voltage meter; AT89C51 SCM; high precision
