GM328 M328 LCR 2017 version transistor meter tester

Here are two similar transistor testers which I bought from eBay 3 months ago. They are almost identical. The red one(left) is a DIY kit and uses standard components but the green one(right) uses SMT components and is a finished product. Each is sold less than USD20 in eBay. They have the same firmware so that the manufacturing flaws are the same. You turn the knob up and down to choose options and "press and hold" will get you the options which you choose. Both devices need to be calibrate which are clumsy to do. You must short 3 test terminals together with a tiny wire and then use a electrolytic capacitor for test reference. In the video, I use an electrolytic capacitor(1000 uF) and two 8550 transistors as examples to test. The last 8550 transistor with used/bent feet is broken and it will show in the device that these are two resistors in series. The device cannot tell you that your test subject is partially broken. However, you know something wrong with this 8550 transistor if the displayed information is incorrect. You may compare the second test subject (new 8550 transistor) and the third test subject(broken 8550 transistor). Single button operation is clumsy to use and the firmware has bugs. And the calibration is difficult to do unless you have a pocket of electrolytic capacitors of different values on hand. Both devices are made for electronic hobbyists only.