Dear customer: Thank you for choosing my store for shopping. The following are the matters needing attention for shopping: A. Economic transportation: detailed tracking information will not be included. Most of the packages will cause delayed delivery within the expected delivery time, so you need to be patient B. Each product link: There will be different option variants. If you do nt know how to select the product you want, please contact me, I will be honored to solve this problem for you. C. When you receive the package, there is product damage / product problem / error product and shipping problem, please contact me in time, I will solve it for you D. If you are a r / distributor, a large number of orders and quantities, to provide you with factory prices, and hope to be honored to reach a partner with you GOOGZON store: I wish you a happy life The measurement range of the voltmeter is 0-30V. This voltage is only a measurement signal and cannot be used as the working power supply of the voltmeter. Therefore, the voltmeter needs to provide 5-30V DC voltage from the outside as the working power supply. Among the three wires, the black wire is the common negative pole, the white wire is connected to the positive pole of the measurement voltage, the red wire is connected to the positive pole of the working power supply, and the total negative pole in the meter Measuring range 0V-30V / 0-100V Two wires =DC30.0V Note: Input voltage higher than 30V may be permanently damaged Three wires = 0-100V, but can not use a large current, otherwise it will damage the product Allowable error1% When it is greater than or equal to 10V, the error is 0.3V; Error 0.10 when less than 10V Input impedance>100K Operating currentRed<23mA, green<18mA, blue<13mA Refresh Rate About 300mS once Display mode:Three digit 0.56 "LED digital tube Display Color:Red / Green /Blue /Orange /White Lead Length:20cm Overall dimensions:48 x 29 x 22 mm, L x W x T; Mounting hole:46 x 27 mm Working Temperature :-10~65