There is AC that runs threw a automotive electrical system. No matter how good the recifier is there is still a bit of a sine wave on top of the DC. That AC can and does induce noise into certian setups.
it's a valid theory - but I disagree that it is a noise source in a car. Those are a few hundredths to a few tenths of a volt ripples that are absorbed by the battery. It is, however, a great explanation from a stumped technician to an uneducated customer.
Hense alternator wine. Noise induced into audio system. Ever wonder why its not present when the car isn't running?
no, didn't care, never had much in the way of noise problems. The only thing I can think of was in my 79 datsun years ago. It was an issue with the original AM radio. Replacing it with a basic JVC eliminated the noise. In hindsight I would say it was a ground loop issue with the cheap stock radio, but I'm more than willing to admit I'm not sure.
In normal people terms how much RF it takes to make something fail and how much RF something gives off. Everything with a transistor unless its countermeasured gives off RF.
Are you talking about radiated noise? All I can say about radiated noise is that the industry experts I have communicated with dismiss it as a non-issue in a car. I haven't studied it, I know nothing about it personally.
So when I say you're wrong. Hate to break it to you buddy but your wrong.
Great - everything I've learned about induced EMI on my own good time because I'm interested in electronics and science in general says otherwise. And I couldn't care less about your
Marketing
Electronics to dumb
Consumers with deep
Pockets certification.
You don't need high current AC to indunce noise. I can induce noise into a car audio system with a single transistor. Since speakers play sine waves any induced noise into said wiring will be picked up amplified and played.
(indunce --
-- that's funny)
Again - I have no idea how a transistor would effect noise, or why I'd want to know. I would expect, however, that if it were switching at a frequency in the audible bandwidth it could be a source of audible noise.
Also, I don't know how much current is needed, but I know it takes at least a volt of AC fluctuation. Any less is not enough for it to be AUDIBLE. Any more and you have a defective alternator.
Also who cares about static magnetics, the AC current running down your powerwire for your amplifier can create a RF field. Which in turn can couple itself to any metal object and create a mild magnetic field. Enough to effect anything? Probably not.
I don't care about static magnetics as it relates to this topic either, but I stated magnetic fields
in general don't induce audible noise in adjacent wires. You said I was wrong. The speaker magnet reference was simply pointing out that a magnetic field -"in general"- which a speaker magnet clearly produces - would not be a noise source.
Again, there is AC flowing down your power wire. That ac can induce noise. What else would you like to know.
nothing. I'm sure some small "noise" component is there, and that AUDIBLE noise is not.
If you happen to have a powerful amp and some speakers laying around - try this -- connect a pwr and ground wire to the batt. Run them on the ground away from the car and hook up the amp. Run some signal wires from whatever's convenient, an mp3 player ought to work fine - connect the speakers and turn it up. Do whatever you want with the pwr/signal/speaker wires - twist them, braid them together, loop them however you like -- TRY to produce audible noise - you'll find that it can't be done.
I've said my peace. Hopefully you've said yours.
I don't think either of us has been particularly moved by the other's thoughts.
If we're lucky a few people got something out of the discussion. If not I guess we've both wasted our time.
