The DIY Solution for Testing Transistors, Capacitors, and More

Whether you're new to electronics or you’ve long since lost track of your first project, having the right tools is an absolute must. One of the most useful among them is a multi-component tester. It’s perfect for identifying and analyzing the assorted LEDs, transistors, and resistors that tend to pile up — whether they come from bulk purchases, salvaged gear, or years of tinkering.

There are plenty of commercial options available, but if you’re willing to do a little work, Easy Tech has another option that can save you some cash. Using this DIY approach, a multi-component testing tool can be built for just a few dollars in parts. When complete, it can test transistors, capacitors, resistors, and more.

You’ll only need a handful of common, inexpensive parts to get started. An Arduino Nano board does most of the work. It is connected to a 0.96-inch 128×64 OLED display that serves as the user interface. An MT3608 DC-DC step-up converter module and a 14500 battery provide the power, with a TP4056 module thrown in for easy USB charging. A ZIF socket provides a way to connect the components that are being tested.

You won’t even need a 3D printer to build this device. Easy Tech demonstrated how sheets of PVC can be cut to size and glued together to form a perfectly nice enclosure on the cheap. Once the circuit is assembled and housed in the case, the Arduino is flashed with custom firmware to turn it into a functional component tester.

Using the tester is a snap: simply insert a component into the ZIF socket and press a pushbutton on the top of the case. Within moments, the display reveals the component type along with relevant technical data, such as the resistance.

The circuit diagram and source code have been made publicly available. Go grab them if you’d like to add a component tester to your toolbox.