0~20V range DC meter link: https://www.pcbway.com/project/shareproject/Digital_voltmeter_head.html this time increased to 0~200V.

Modifying the value of the voltage divider resistance can also further expand the range.

The accuracy of times is one digit after the decimal point, which actually feels faster than the meter’s response speed

This design is a voltmeter head based on the chip ICL7107,

with a range of 0~200V, which can be expanded

 ICL7107 is an analog-to-digital conversion chip with high accuracy, low noise,

low temperature drift, high stability and long life; segment code output,

which can directly drive the digital tube without any program

This project mainly includes ICL7107 drive circuit, four common anode digital tube circuits, etc.

5V power supply, the voltage to be measured is connected through another terminal

After the components are welded, there is no short circuit in the meter measurement. Connect the power supply,

pin 1 is 5V, pin 26 is about -3V~ -4V, and pin 36 is 1V, which is the normal state. At this time,

the digital tube should display three 0s. If not, please check the components and welding conditions