I while ago I was looking for a cheap transistor test. I did toy with the idea of building one. There are several designs based on traditional techniques of basically substituting the transistor on test into the circuit and lighting an LED or something to indicate that it was working correctly. The problem was that for testing PNP and NPN and the different lead layouts meant it wasn’t going to be as straight forward as I’d first thought.
What I eventually found was far better than I ever could have imagined, hoped or believed possible. If you think that seems over the top please read on and I think you’ll see why. As electronic test equipment kits go I find it hard to fault this one.
Imagine a device that had a test socket that had multiple connections on it and it didn’t matter which component legs connected to which. Imagine if you didn’t even know what the device was and you just pressed a button and got the results on screen.
That’s in a nutshell exactly what this Yosoo(TM) UK-SMD/DIP Transistor Tester Diode Triode Capacitor ESR LCR Meter PNP NPN MOSFET does. What you get is constructed boards with all the hard SMD stuff already on it. You just have to solder on the push button, battery connector, socket and then bolt on the display module and solder that. It only takes a few minutes to finish and you may wish to mount in in a case. I intend to do this when I finally get around to it.
The completed kit has a zero insertion force socket with various numbers around the edge of it. 1,2 and 3 all you have to do is make sure that the three transistor terminals each connect to a 1,2 and 3. The way they are arranged makes it fairly easy to just drop a transistor in. It doesn’t matter what terminals connect to where. The tester does it all for you. It informs you of the emitter threshold voltage and the current amplification factor, whether the transistor is PNP or NPN and the pin out.
Displaying the pin out is very useful if you just want to double check a component as there are so many variations with transistors.
For the cost this alone would make alone of the most useful electronic test equipment kits that I have come across. Add that to the fact that it can measure resistors. Again useful to double check the value is what you think it is. I’m not sure what the actual accuracy is but as you can see from the picture below the 100 ohm resistor is actually reading 977.9 ohms so you could match resistor values easily with that resolution.
You can also measure capacitors as you can see in the picture below. Polarity doesn’t matter but you need to make sure that they are properly discharged before you connect them as you can damage the tester if you don’t. Large value capacitors can take a while to test and measure, sometimes up to a minute. All other components only take a second or two.
You can also test diodes. Shown below are pictures of a diode and a zener diode being tested, as well as MOSFET’s, JFET’s and thyristors.
Inductance can also be measured in exactly the same way, just connect it up to either terminals 1, 2 or 3 and it will identify and measure it. If you wanted to you could connect up a custom socket or leads as there are pads available clearly marked you could solder to.
Having built various electronic test equipment kits over the years I can easily say that this is the best component tester and measurer that I have ever built. I wish I had one years ago. As soon as I had built and tried it I ordered another one for a spare. It’s really that good. I can’t imagine anyone who’s interested in electronics not to be impressed.
It's worth noting that this item in a very similar form is available from Amazon as a pre-built item direct from the UK.