OK, schematic looks right now Large filter caps (> 100uF) by themselves wont solve the spike problem. You will need some series inductance (try 100uH), and some lower-value caps (0.1uF) in parallel because larger caps dont filter high-frequency noise very well. Also be sure to have a series diode from the +12V automobile power to protect against reverse-polarity. I recommend a fuse as well. As far as what L & C values to use for the filter, the values I guessed at get you a corner frequency of a few kHz. You might want to put a scope on your car and see what noise you get during engine-idle while the battery is charging; I'm guessing the alternator is the biggest source of low-frequency noise, but it could also be the ignition system. I've never looked; always been curious.
Plan on noisy signals from your sensors; there's all sorts of electrical noise under the hood. There's a lot of clever automotive engineers with many years of experience who have solved this problem, and hopefully published some technical papers. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/e4ae67ce-3349-4049-9a60-75eccee8d57d%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
