Features Wide Application: The USB tester can be used to measure battery voltage, current, discharge capacity, etc, can be used to test the charging voltage and current of electrical appliances such as mobile phones, tablets, mobile power supplies and so on. Easy Viewing: The USB tester equipped with LCD backlight display, which can display voltage, current and battery capacity data at the same time for easy viewing. The backlight LED gives an alarm prompt by flashing. Press the button and the LED screen will light up for 30 seconds. Data Storage: The USB voltage ammeter meter support multiple sets of detection data saving, power down saving function, can detect the output battery capacity of mobile power supply. The data can be cleared through the button, and the data can be protected from loss. Directly Read: You can plug the USB male connector of the detector into a 5V USB charger, plug the female jack into a mobile phone, tablet, mobile power supply and other devices, and directly read the voltage and current parameters. Use Notices: Test the output voltage and current of the power supply and mobile power supply (it must be matched with the load device), plug the detector USB male into the 5V USB charger, and plug the bus into the USB load device to directly read the voltage and current parameters. Specification: Condition: 100% Brand New 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 Instructions for Use: 1. 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. 2. 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. 3. 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. 4. Data reset: Press and hold the button for more than 3 seconds to reset the data in the current group. Package List: 1 x USB Tester Package List 1 x USB Tester