Voltage and Current Measurement: Simply connect the USB male to a 5V charger and the female to your phone or device to instantly read voltage and current parameters. Measure MicroUSB Cable Quality: Connect your phone and a 5V charger using the tester. First, note the voltage. Then, insert the MicroUSB cable into the tester's MicroUSB port and note the voltage again. A smaller voltage gap indicates a higher quality cable. Measure Mobile Power Output and Efficiency: Connect the power bank to your phone, turn it on, and reset the capacity data to zero. Plug in the phone repeatedly until the power bank shuts off automatically. The displayed capacity is the mAh output of the power bank. Data Switching: Click the button to switch to the next dataset, double-click to switch to the previous dataset. Data Deletion: Press and hold the button for more than 3 seconds to delete the stored data. No professional wiring needed! Easy to use – just plug into the USB port, discharge, and charger to monitor your device's current and voltage and calculate battery capacity. Detect the charging capacity of tablets and mobile phone batteries to determine battery degradation and if restoration is needed. Detect the power bank's discharge capacity and calculate its conversion rate. Detect the charging current of your digital device. Measure the working current of 5V routers and other 5V USB port devices (like USB hubs). Comes with a USB input cable and a MicroUSB port for alternative input options. Connect one end to the power supply/power bank (default is USB interface, i.e., 5V) and the other end to the load (e.g., a mobile phone). Parameter: Input Voltage: 3V-15V Voltage Resolution: 0.01V Test Current: 0.05A-3.50A Current Resolution: 0.01A Capacity Range: 0-19999mAH Accuracy: ±1% Line Loss: Approximately 0.1 ohm Test Content: Battery voltage, current, discharge capacity (10 datasets total) Color: White Quantity: 1 piece