Last night I was playing around with a 2n2222 transistor, a push button switch and a DC motor and I kept blowing out transistors and I don't understand why. I set up 2 breadboards following the schematics below but only one worked. I thought maybe I had something backwards on the second one. I took it apart and put it back together multiple times but it just was not working. Finally I thought maybe there was some problem with the transistor in the "No work" circuit. So I got a brand new one and put it in the working"circuit. Worked fine. Then I put it in the "No Work" circuit and it didn't work as expected. Put it back in the working one and it did not work. That's when I realized I was blowing them up. I just don't get why. Can anyone explain this?Thanks.
After I drew those up I decided to try resistors. I just grabbed what was handy, 1k, which was overkill because in the "works" one it made the motor turn, but very slowly. In the second it still destroyed the transistor. Then I gave up and went to bed.I'll have to play some more tonight.
So your motor ran slow because the base resistor was too high a value and the transistor was not fully turning on.
Are you double sure you have correctly identified the base, emitter, and collector leads?Lefty
Quote from: retrolefty on Mar 01, 2011, 05:33 pmAre you double sure you have correctly identified the base, emitter, and collector leads?LeftyWell now that you mention it, no. It just dawned on me. I think I read that when reading the datasheet for a transistor it's the opposite from reading an IC. That is, with an IC you assume you're looking at it from the top down to read it's pinout. When looking at a transistor datasheet you are looking at the diagram from the bottom. Can you confirm this or am I making that up? If it's true I'm all backwards.
NPN Silicon TransistorRed: coll, Green: emit, Blue: baseCurrent gain: Hfe=196Test current Ic=2.50mABase-emitter Vbe=0.78VTest current Ib=4.62mALeakage current Ic=0.00mA