0.28inch 0-100V Three Wire DC Mini Voltmeter

SPECIFICATION

• Power Supply:   3.5~30V
• Measured Voltage:   0~99.9V (3-wire mode)
• Working Temperature:  -10～+65℃
• Measure Speed:  200ms a time
• Accuracy:  3%
• Display type: 0.28″, Red, 3 digit seven segment
• Dimensions:  30mm x 10mm x 10mm

This voltmeter has three wires, and they are:

• Yellow: anode (+) of measured voltage
• Red: anode (+) of power supply for the voltmeter
• Black: common cathode (-) of measured voltage and power supply

The typical wiring of this voltmeter is shown in figure below:

With this wiring the voltmeter can measure up to 100V. If the actual measured voltage is higher than 3.5V and is lower than 30V, you can also merge the red and yellow wires and simplify the wiring like this:

In this case the measured voltage will also work as the power supply for the voltmeter.

This voltmeter has been calibrated before leaving the factory. However if you want to get better accuracy,  you can calibrate it by spinning the potentiometer on its back.

Spinning the potentiometer clock-wise will reduce the displayed voltage value.