Did you find an LCR-T4 Component Tester in your Christmas stocking this year? At around $10, it’s a pretty neat gift for electronics makers.
Every year, my wife gives me a $15 budget for family and friends stocking stuffers. I usually apply this to myself, as well. This Christmas, I stuffed my stocking with the LCR-T4 component tester, around $10 on e-bay. So, what exactly is this thing?
Simply put, it is an Arduino-based device you can use to test a variety of electronics components. These include capacitors, resistors, inductors, diodes and transistors. Just plug them in across some terminals and push the button. The LCR-T4 will figure out what kind of component is connected and read its value on a small screen. In addition to reading values, you can also use this thing to identify unmarked components and some key parameters, especially useful for mystery transistors.
You can buy the board alone, or add an acrylic case. The whole thing runs off a 9 volt battery. You won’t find an on-off switch. It turns itself on when you run a test, and closes down after around ten seconds. You will find assembly instructions online, if you need them.
The usable range for passive components is fairly wide, including capacitors down to a few pF and inductors to a few nH. I ran some tests to compare performance with other testers. All I can say, good enough for $10.
LCR-T4 Component Tester – How It Works
The heart of this device is an ATMEGA 328 – basically an Arduino – with some firmware. Generally, LCR meters work by measuring voltage, current and phase across a device under test.
Arduino provides pulsed output lines and an analog-to-digital converter. So, all you need to do some frequency sweeps across the DUT and read back results. Some pretty sophisticated algorithms then process results and display measurements on a screen.
If you are really keen, you can build your own version of the LCR-T4 component tester using an Arduino, as shown in a variety of Instructables. Reading the Arduino code will provide insight into how these work.