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| The 80s Man:
--- Quote from: ahofle on March 22, 2006, 03:06:47 pm --- Well the lights do work and flash, but they are the inverse of what they should be. Thx, Andy --- End quote --- The same thing happend to me the first time I made a driver board. My problem was that I use NPN transistors in stead of PNP ones. Dumb me.. |
| ahofle:
LOL OK that's my problem too then (this board has NPN transistors). Thanks for that clarification! Off to radio sack I go. |
| whammoed:
--- Quote from: The 80s Man on March 22, 2006, 08:30:52 pm --- --- Quote from: ahofle on March 22, 2006, 03:06:47 pm --- Well the lights do work and flash, but they are the inverse of what they should be. Thx, Andy --- End quote --- The same thing happend to me the first time I made a driver board. My problem was that I use NPN transistors in stead of PNP ones. Dumb me.. --- End quote --- Yep, thats probably it. The first sites I read simply said that PNP and NPN transistors "did the same thing". Didn't actually matter for me since I am using advmame and have greater control over whether the leds are off or on. Switch out the transistors and all should be well I would think. |
| whammoed:
--- Quote from: The 80s Man on March 22, 2006, 08:30:52 pm --- --- Quote from: ahofle on March 22, 2006, 03:06:47 pm --- Well the lights do work and flash, but they are the inverse of what they should be. Thx, Andy --- End quote --- The same thing happend to me the first time I made a driver board. My problem was that I use NPN transistors in stead of PNP ones. Dumb me.. --- End quote --- Also, I don't think it was too dumb to think you could substitute one for the other. A few popular hits from googling don't quite reveal the difference between the two. Here is a site that does: http://encyclobeamia.solarbotics.net/articles/bip_junct_trans.html There's at least two of us who thought it would be just fine. ;) Yes, I am still dumb, but I'm just not sure this is a defining moment... :D |
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