LCD Display Backlight USB Detector Ammeter Voltmeter Charging Capacity Tester Meter 4-30VBlack Condition: Item Type: USB Tester Material: ABS Color: Black, White (Optional) Input Voltage: 4-30v Voltage Resolution: 0.01V Test Current: 0.05A-3.50A Current Resolution: 0.01A Capacity Range: 0-19999mAH Accuracy: Plus or Minus 1% Road Consumption: 0.1Ω Test Content: Battery Voltage, Current, Discharge Capacity (10 sets of data in total) Instructions for Use: 1. Measuring voltage and current: plug the USB male head into a 5V charger, plug the female jack into a mobile phone and other devices, and directly read out the voltage and current parameters 2. Measure the quality of MicroUSB cable: plug the mobile phone and other devices into the female jack, first plug the 5V charger with the male head of the machine, remember the voltage, and then use the Micro USB cable from the 5V charger to the Micro USB hole of the machine to remember the voltage and voltage gaps The smaller the MicroUSB cable, the better the quality. 3. Measure the output capacity and efficiency of the mobile power supply: first connect the machine to the mobile power supply, turn on the mobile power supply, long press the button until the capacity data returns to zeroing, insert the mobile phone and charge it multiple times until the mobile power supply is powered off and automatically shut down. The next time the machine is turned on, the display capacity is the mAH output from the mobile power supply. Note that this mAH is much smaller than the nominal mAH. The output mAHxoutput voltage 5V / battery mAHxbattery voltage 3.7V = mobile power efficiency. 4. Data switching: click the button to switch to the next group of data, double-click the button to switch to the previous group of data. 5. Data reset: Press and hold the button for more than 3 seconds to reset the data in the current group.