Which way does current flows
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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=74236
Printed Date: May 05, 2024 at 6:39 PM
Topic: Which way does current flows
Posted By: shaz13230
Subject: Which way does current flows
Date Posted: March 10, 2006 at 6:37 AM
Hi In regards to an automotive, does current really flow from the negative terminal towards the positive terminal? And if this is so, then why are wiring diagrams layed out in a manner which shows the current flows from the positive. I am trying to learn about electronics, but its just so confusing. Also, I might sound silly, but can someone also explain this. If current flow is made up of moving electrons (negative), does this mean they only travel through negative wires? If this is so, then what does a positive wire do? Apologies for my ignorance. But can someone please answer these questions for me? Thanks
Replies:
Posted By: electrostatic
Date Posted: March 10, 2006 at 9:12 AM
there are two schools of thought on current flow. hole-flow and electron theory. the electrical engineering field uses hole-flow and the scientific field uses electron theory. hole-flow describes current flowing from the positive side of the circuit to the negative side. electron theory describes electrons flowing from the negative side of the ciruit to the positive side. they both describe the same thing just from different perspectives. the automotive field uses hole-flow. the important thing when analyzing a circuit is to pay attention to polarity. a wires designation as positive or negative describes what side of the power supply its connected to.
Posted By: shaz13230
Date Posted: March 10, 2006 at 12:30 PM
I have read many books, but you made the theory sound so simple. Thanks alot for that. Much appreciated. So in regards to the positive and negative wires, can these be thought of as one-way roads. Also, can a positive wire be connected to a negative wire at any given time? When positive wires are connected to a component, does it mean that a negative wire must come out from the other side. Apologies for sounding so thick, its just that their method of exlaining this in college isnt very helpful. Thanks
Posted By: geepherder
Date Posted: March 10, 2006 at 4:03 PM
A dc circuit has a power supply (like a battery, for example), and a resistive load (like a light bulb), which separates the positive and negative sides of the circuit. If you were to just touch the positive side directly to the negative side, you would cause a short circuit, and because there's no load (basically no resistance), you'd blow the fuse. Without a positive or negative, the circuit is not complete.
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Posted By: electrostatic
Date Posted: March 10, 2006 at 4:29 PM
save the one-way road analogy for diodes. wires are conductors (material with alot of free electrons) that allow charges to move freely. if you have a higher state of energy on one side of the circuit current will flow to to the other side of the circuit to equalize the charges.
Posted By: justtegit
Date Posted: March 10, 2006 at 4:43 PM
shaz13230 wrote:
Apologies for sounding so thick, its just that their method of exlaining this in college isnt very helpful. Thanks
Heh, come here to Georgia Tech and take Physics II...it was explained pretty well to me... (damn that class sucked ass, lol)
Posted By: shaz13230
Date Posted: March 13, 2006 at 5:48 AM
Hey Many thanks for all your posts, I think the replies I am getting from this website are far better and helpful than the replies I get from my lecturer, I cant seem to understand a single word he says...must be the long moustache! Thanks again Shaz
Posted By: auex
Date Posted: March 13, 2006 at 10:48 PM
electrostatic wrote:
there are two schools of thought on current flow. hole-flow and electron theory. the electrical engineering field uses hole-flow and the scientific field uses electron theory. hole-flow describes current flowing from the positive side of the circuit to the negative side. electron theory describes electrons flowing from the negative side of the ciruit to the positive side. they both describe the same thing just from different perspectives. the automotive field uses hole-flow. the important thing when analyzing a circuit is to pay attention to polarity. a wires designation as positive or negative describes what side of the power supply its connected to.
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Posted By: placid warrior
Date Posted: March 13, 2006 at 11:27 PM
thought this sounded familiar. Reading the MECP study book...exactly what electrostatic wrote except they called the "hole-flow" 'conventional current flow' and stated it as current flowing from higher voltage potential (+) to lower voltage potential (-)...in case that helps at all.
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