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General Mach Discussion / Re: Help with digitizing/probing
« on: March 24, 2013, 09:20:15 AM »
I am a little confused. When I am probing, the signal is active high (probe triggers when 5v is present.) The leads inside the probe hold the signal grounded until probe touches. So when I get these "phantom points", it must be seeing 5v. I understand how this could be noise, but if I put a cap across the input, it'll stay high longer. If it stays high longer, won't the routine fault? And how would I size the cap to try it? I keep think I need something inside the probe to hold the signal low better, like pull down resistors. I just don't know how to wire it.