This voltmeter comes with a 0.28 Inch 3-digit LED 7-segment display. The module is tiny enough to fit any project. It comes with 3 wires and the connection is really simple and requires just a few minutes to configure. You only need to connect the power supply and source to be measured and the result will be in LED blinking. 

If the voltage is up to 10V then 2 decimal places will be shown and when it measures from 10V to 100V then 1 decimal place will be shown. The module has inbuilt reverse voltage protection and comes with a potentiometer for better accuracy that users can calibrate. 

Wires and Connection

• BLACK: Ground ( you can short the ground of power supply and a voltage source to be measured)
• RED: Positive of power supply
• YELLOW/WHITE/BLUE: Positive of the voltage source to be measured 

When the voltage to be measured is from 3.5V to 30V then you can short red and yellow wire to simplify your circuit. In that case, the voltage source to be measured will work as a voltage supply.

Features

• Reverse voltage protection
• Potentiometer to calibrate
• Compact size to fit in any project
• Easy to measure voltage
• Simply wiring and connections 
• Very lightweight 
• Can work as 3 wire as well as 3 wire mode

Specification

• Power supply: 3.5V-30V
• Maximum working current: 30mA
• Current consumption: 10mA
• Voltage measuring range
  • 3 wire mode: 0V-100V
  • 2 wire mode: 3.5V-30V
• Accuracy: 0.1V
• Measure speed: 200ms/one time
• Operating temperature range: -10℃ to +60℃

Application

• Mobile battery indicator
• Car or motorcycle battery indicator
• Battery voltage indicator 
• And project where voltage needs to be display