![]() ![]() The hardware is used in many different modes to achieve a result. The internal analog switch resistances are measured, the internal comparitor offset is measured. This transistor tester is a masterclass in making use of the internal hardware of an atmega. If you program the 328 out of circuit you can ignore this jumper and the 6 pin header. The Reset jumper wire is needed if you program in circuit. You should always try to avoid supplying power to a circuit from both the board and your programming device, this is not be a good thing as you should never let the beams cross. Even if you program the 328 in circuit just make sure the board is powered by keeping SW1 closed. You probably don't need the 5V jumper wire to the program header. I do not claim any competence with schematics or board layout so use at your own risk Board Notes: The two jumper wires are optional. I've attached the Eagle 6.3.0 files for my single sided diy version of Karl-Heinz Kubbeler V1.06k if anyone is interested. Still, a nice little project if you have a way to program up a Mega328. I matched the 680r and 470k resistors to the third digit, maybe better matching would help. A 0.01% 5k resistor reads 5066, so about 1.3% which is good enough for a quick test. Just tested the accuracy of my home made version. Anyway, a cute little gizmo, certainly worth the $20 and it seems reasonably accurate within the scope of it's limitations. A 100nF capacitor is required at one point (step 4, IIRC). ![]() On-screen directions kind of guide you through each numbered step if you scratch your head long enough deciphering them. I accidentally discovered a self-test/calibration mode by connecting all 3 leads to each other and pushing the button. That really IS a diode that got mixed in with the SCRs - look at the number: Ok, here's a real SCR (GAC indicates which lead connected to the Gate, Anode and Cathode, respectively): But an LM317 threw it for a loop: The documentation is non-existent. Oh well, at least I can figure out from that if it's PNP or NPN: FAIL again - Ooops, no it's not. This is a power transistor, not a pair of diodes. (To be fair, it's rated 600v/40amps): Partial Fail. ![]() It tells you what it is and the value: A 1% resistor: A capacitor (this one must have real low ESR - usually there's a value in ohms): A transistor (note that it tells you if it's PNP or NPN and which lead is connected to what, gain and forward voltage): How about an inductive load? FAIL! That's an IGBT, not a capacitor. Operation is simple: connect the component (leads in any order), push test. I put it in a project box, added some leads and a switch and hooked up a 9v battery. What the heck, for $20 it looked like it could be fun, especially for a dilettante like me with a drawer full of oddball small signal mystery transistors. A few weeks ago I stumbled over this fellow on fleabay. ![]()
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