The Digital USB In-Line Voltage Charging Current Meter is a pretty nifty tool that lets you measure the working voltage and current output for any USB port or project.
Simply plug it into a USB port and your USB device and its 7-segment LED display driven by an on-board microcontroller will alternately indicate the voltage and current. By using this tool, you can troubleshoot common problems associated with the charging process – whether your device is heating up, not charging or charging too slow.
Identify the cause of the problem such as charger compatibility, too old charger, or effect of USB extension cables. You can even use it to check the power consumption of USB peripherals and devices like Raspberry Pi, USB Wi-Fi adapters, and USB storage devices.
A definite must-have to monitor and care for your USB powered device or project!