Design of a simple DC digital voltmeter

The simple digital voltmeter is made of the ATMEL 8-bit MCU(Main Computational Unit), AT89S52 and national semiconductor's ADC(Analog-to-Digital Converter) 0804, including a certain number of components. The system uses the AT89S52 MCU as the main controller, which processes the acquired analog voltage and realize LED(light-emitting diode) digital display by dynamic scanning. The voltmeter can measure the DC(direct current) voltage in the rage of 0 ∼ 5V and display the measurement results by the four LED digital tube. Because of fewer components, low cost, automated adjustment, high accuracy measurement, stable performance, the voltmeter has a very good application prospect.