Reference direction of electrical current in teaching/books

Hello,

Recently I ran into a book that teaches that current flows from the negative to the positive terminal (i.e. across a resistor). This implies electron flow and is opposed to all examples I've seen in other books.

Perhaps someone knows of a resource that discusses this issue? I.e. which way is more correct to teach, how have the current symbolics developed, etc?

Thanks

Reply to
eliben
Loading thread data ...

formatting link

--
Rich Webb     Norfolk, VA
Reply to
Rich Webb

Is this really what the OP wanted? (Not being argumentative... but it doesn't really seem to be helpful information, though true).

OP - Amazingly, I cannot find (in a quick Google) a lucid web explanation of the concept, but what you want to research is "passive sign convention". All the good references I could find are in printed books, nothing online seems to be worth reading.

Reply to
larwe

Well, he does tend to go around the barn and over the fence to get to the front door. ;-)

--
Rich Webb     Norfolk, VA
Reply to
Rich Webb

Is this really what the OP wanted? (Not being argumentative... but it doesn't really seem to be helpful information, though true).

OP - Amazingly, I cannot find (in a quick Google) a lucid web explanation of the concept, but what you want to research is "passive sign convention". All the good references I could find are in printed books, nothing online seems to be worth reading.

I think the OP would do well reading the material provided by Rich. It gave enough backround for the OP to answer his own question.

Tom

Reply to
Tom Biasi

Try Googling "Conventional current". Conventional current is taught as it is easier to understand - positive to negative. Flow of electrons is opposite to conventional current as they are repelled by the negative terminal and attracted by the positive. Kids cannot understand this..

--
Bill Naylor
www.electronworks.co.uk
 Click to see the full signature
Reply to
Electronworks.co.uk

formatting link

Reply to
gearhead

"eliben"

** Search on "conventional current flow":

formatting link

formatting link

Lots more to be found.

..... Phil

Reply to
Phil Allison

The military and some tech schools (Heald, I think) start with electron flow, and later switch to conventional current. This confuses the hell out of the students, some of whom never get it right. Universities (physics, chemistry, engineering) always use conventional (pos to neg) flow math.

John

Reply to
John Larkin

From that page:

Here are some basic ground rules:

  • All resistors are either positive or negative uniformly. Which means that if you consider one resistor to be positive (which is the common case) then all the resistors are positive.
  • At least one source is the opposite sign of the resistors. If only one is present then that is the one.
  • Always start by making your loop.

This is insane gibberish.

John

Reply to
John Larkin

By convention, a resistor's _current_ flows from positive to negative (note that a power supply 'pumps uphill', and forces current to flow from negative to positive).

This is (or should be, at least) kept distinct from _electron_ flow, which is opposite of current. If some tidy-minded person wants to teach you that current flow and electron flow both go in the same direction, they do you a disservice by confusing the hell out of you and those around you when you go talk to the other 99.999% of humanity.

--
http://www.wescottdesign.com
Reply to
Tim Wescott

Is it correct to say that there's absolutely no advantage of one way over the other and it's purely a matter of convention?

Of course, it seems that the accepted symbols follow the pos to neg flow - for example the diode symbol makes it clear the conduction is from anode to cathode, and the arrows of transistors also follow conventional flow.

Eli

Reply to
eliben

It might have been better to call electrons positive, but the convention pre-dates the discovery of electrons. So it's a convention we're stuck with.

Things other than electrons can carry current too, like positive ions and proton beams.

Ammeters and voltmeters too.

John

Reply to
John Larkin

means that if you consider one resistor to be positive (which is the common= case) then all the resistors are positive.

nly one is present then that is the one.

Yup, that's a pretty crappy article. You can't believe everything you read on wiki.

George H.

Reply to
George Herold

In 22 years of electronics, I have never met anyone who uses electron flow as the norm. Keep it conventional - positive to negative - and you will fit in with the crowd and not confuse the hell out of everyone

(it looks like Phil agrees with me, which gives me a warm feeling too (!))

--
Bill Naylor
www.electronworks.co.uk
 Click to see the full signature
Reply to
Electronworks.co.uk

EW > (it looks like Phil agrees with me, which gives me a warm feeling too (!))

Like wetting your pants?

Reply to
Greegor

!!!!

Now that made me laugh!

--
Bill Naylor
www.electronworks.co.uk
 Click to see the full signature
Reply to
Electronworks.co.uk

It's easy. Electrons are negative and are attracted to the positive. Understand that (as in electron tubes or semi conductors) and put it aside. Now; as a convention it was decided long ago that current flow within an electric circuit shall be shown as flowing from postive to negative. For example: Positive terminals on things such as batteries are often marked or shown in red. Negative terminals in various other colours, often black, green. blue etc. When working on a circuit one assumes electric current flows away from the positive part of any circuit towards something less positive or in other words negative to the starting point.

Reply to
stan

College boys use positive charge flow - techies use electron flow. (electron flow is clearly right - consider the CRT! ;-) )

Just remember which system you're using, and be consistent - they're identical, but with all the signs swapped. :-)

Hope This Helps! Rich

Reply to
Rich Grise

Not in the USAF, they didn't. We used electron flow from the start, and stuck with it. It's really the only way to understand how maagnetrons and klystrons and traveling wave tubes and backward wave oscillators and such actually work. >:->

Either way works equally well, just swap all of the plus and minus signs. ;-)

Cheers! Rich

Reply to
Rich Grise

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.