A simple tool to test LEDs if they are working or to check resistance values for LEDs. If looking to test LEDs for brightness, this is a great tool simply with a power supply of 5, 9, or 12 volts (selectable) and no external test equipment, you can test LEDs for functioning or for brightness with a selectable resistance to match your project. Seven resistance values are set in the tool, selectable with a header pin jumper, 220, 330, 470, 1K, 2.2K, 4.7K, and 10K resistance values.

You can also use this tool with a resistance decade box to fine tune what resistance you need, hook probes are needed for this.

Current can also me measured using a multimeter, hook probes also required for this, to see what current a selected LED is drawing with relation to a resistance value.

This is an easy to assemble project that would make a useful tool for your workbench. You need just basic schematic reading and soldering skills for this, and would make a great project for a school to teach soldering, schematic reading, and how all the parts are working together.