From the Electronics Lab: Our Transistor Tester

Posted: October 16, 2017 11:19 am

At first I was thinking of doing a blog post about the multimeter, but instead I choose this guy the QS2015-T4. Fairly unassuming and in a box that might be marked “transistor tester”. Amongst the arduino and sensors, this clever guy a ATMEGA328P with some neat firmware. On the front is a screen, and a socket and a button that does stuff. Pictured here it’s interrogating the transistor we use in basic electronics. So how do you know which way to put it in the socket? You don’t, and you don’t care.

12864 Mega328 ESR

There is a 1, 2, 3 on the board next to the socket . Make sure you have a different pin in a different socket number. See the 1s at the end? All connected together. Check out the screen though. There is a 1 by the G, a 2 by the D, and a 3 by the S. It told us which pins are what. Pop in the part, push the button It figures out the rest technomagically.

Check out where it says C=1.37nF. That’s a capacitance isn’t it? It reads capacitance too. You suspect a cap being bad you can pop it in this bad boy and it will tell you what the capacitance is. I’m not saying it’s NIST traceable, but if you want to make your 555 timer wiggle and need to check that cap? This do that. Resistors, Diodes, Transistors, inductors. Put it in the socket, push the button, and there ya go.         It does have some limitations. UV LEDs for instance have a high enough forward voltage that it thinks it’s a resistor sometimes. Linear regulators don’t play nice. But if you pull a resistor out and the red looks a LEEETLE orange… or if you just don’t feel like googling what the bands are. It’s way easier to use the transistor tester than to try to balance the Multimeter probes on the resistor leads.

We have another transistor tester, a red one with fewer capabilities, it works a lot the same way. But when Jens Torrel donated this guy I liked it so much, I bought one for myself. If you are just starting out in electronics, there is a different model I recommend. That’s just because it has a bunch of other stuff it can do as you go further into analogue electronics. The QS2515-T4 is perfect for the space because it’s easy to use, tells you what you want to know at the touch of a button, doesn’t take up a lot of space, and frankly, there isn’t really another piece of equipment that does what it does in there. It really is a thing that does the thing.

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