Turn 12$ Transistor Tester Into 200$~600$ Smart Tweezers LCR Meter for SMD Component (and Even More)

About: I am thankful for all of those who don't do anything at all. It’s because of them I do it myself. And I gonna do it my own way. The lazy way: think easy, do lazy.

A month ago, I was looking for a good LCR meter because I have lots of inductor but there is no way to measure them using multimeter. I was search for many LCR meter and they are really expensive. I also have some SMD components like capacitor, LED, diode, transistor, resistor,... laying out ready to use but I can't measure them. They are SMD component and it is really hard to measure as well as hold them steadily when testing. There are lots of smart tweezer online for 24$~200$ but they aren't LCR meter, just RC meter. Smart tweezer LCR meter is expensive tool, 240$ is the lowest price. So I decided to buy a transistor tester then turn it into a Smart tweezer LCR meter which very handy and it worked beyond my expectation

Step 1: Build the Transistor Tester and Gather Parts

The transistor tester (actually it can test all components you already know with 3 pins) is very easy to build, too easy so that I skip the soldering part in this instructable. All you have to do is find the exact component value, place in, then solder it. You only need to pay a little attention on the tacticle switch and the quartz cystal. And I found the 220 ohm resistor (control LCD screen light) is replaced with a 2.2 k ohm resistor which make the screen become dark; just replace it with a 1k ohm resistor.

For this instructable, you'll need:
- Small piece of breadboard

- A piece of plastic or a case

- Soldering tin (best if it has silver)

- A spare tweezer (wide open)

- Wires

- A cutting tool

- Soldering iron

- Heat shrink tubes in different sizes

- A paper clip

- 2 stampler pins if you want to reinforce the tip

Step 2: Make a Component Plug and Build a Case

This device is a tester but the default plug a little bit hard to use. I have to adjust the screw to make the component pin fit to the hole and diffenrent components have different pin size. Since that, I decided to use a small pice of breadboard as default plug, which is the best thing to put your component in. Make a component plug by:

- Use a knife or a saw to cut a small piece of breadboard, size is 5x5 hole. Holes are connected together in vertically

- Use cutting tool, cut the paper clip in short piece then shape it to fit the hole. The middle piece should be in L shape to prevent accidently fall inside, put it in the top of middle column

- Make 2 U shape pin to connect column 1 2 and 4 5

- Put 3 short wires into the hole which had 3 cut pins, twist the wires. Put the other end of the wire into plug slot and screw in. You must pay attention to the number of the wire, should be in 1 2 3 from left to right

- Test some component to make sure it worked. Comlumn 3 is the test pin number 2

I use a plastic cap to make a case for the tester. I cut, shaped the cap and use some hot glue to glue it in place. If you want to use DC voltage plug, don't forget to make a hole for DC socket. I will need to replace the battery later so I just use a zip tight to fixed the cover

Step 3: Turn a Normal Tweezer Into a Smart Twezzer

Take a tweezer, put a small heat shrink tube to cover the tip. The tube must long enough to cover whole tip. The heat shrink tube will insolate test pins with the tweezer; it also support the test pin. You need a black and a red tube to identify the polarity of component as well as wire. The length of the wires should be comfortable to work with (mine are 60 cm)

Make a small loop in the wire, put it in the tip of the tweezer then use another bigger tube to fixed the wire with the tip. Shrink the tube, tin the exposed wire and trim the tip of wire if it too long. Do the same with the other tweezer's tip. You can use a stampler pin to make the tip a little bit smaller and stronger. If both tips meet at a small point then the tweezer is almost done. Use a big shrink tube to fixed the wire on the tweezer as well as the other end. Twist all other part of wire then the tweezer is done!

Step 4: Testing Testing

Now the transistor tester is able to test both SMD and through hole component, even the 0805 SMD LED ( very big SMD component). The tester work as good as an expensive smart tweezer LCR ESR meter. Not only that but also test many other components: transistor, thyristor, triac, diac,.. It's not really a standart smart tweezer but it is a "smart" tweezer now, good enough for a DIYer



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9 Discussions


1 year ago


Can I assemble this circuits without purchasing from Banggood? Pls give a programming Code for Atmega328-PU on Arduino 1.8.1 IDE for DIY-Meter-Tester-Kit-For-Capacitance-ESR-Inductance-Resistor-NPN-PNP.

3 replies

Reply 1 year ago

I did build it and it really easy. But it can't run on a normal Arduino board as it required some others component and it draw more current than max recommended value of an Arduino board. You will need a ATMEL328 IC, an USBASP chip burner, a LCD screen, and some other components. Here are links for code and schematic: http://www.mediafire.com/file/mp2vddyoe1bv4ma/USBasp-%5BProgramming-M328%5D.rar


Reply 1 year ago

Thanks Chelseabun

Again thanks for my queries, its ok but without purchasing the kit or without self assembled, May i can used Arduino Uno R3 Board and other necessary components to make such tester?


Reply 1 year ago

I think it possible. But I haven't working with arduino board yet so I can't help you with this :'( The document may give you intruction so try to read it


2 years ago


could you please post the link to the same transistor tester so i can buy one?

1 reply

Reply 2 years ago

I bought this item on Banggood and its price is the cheapest one on the
internet. Here is the link:
Have fun build it :)


3 years ago

Nice job! Where did you get your components?

2 replies

Reply 3 years ago

I bought this item on Banggood and its price is the cheapest one on the internet. Here is the link: http://www.banggood.com/DIY-Meter-Tester-Kit-For-Capacitance-ESR-Inductance-Resistor-NPN-PNP-p-929603.html Have fun build it :)