Since current flows from - to +, why not use + as "ground"?

Thread Starter

zapp0

Joined Nov 10, 2014
9
Hi,

i'm very much beginner in circuits only understanding the basics, still having problems understanding all the current flows in circuits. Of course one of the things is deciding how to decompose the circuit, which as per this portal is advised to be in the acutal electron flow rather than "classic" flow.

This just leads me to the question, wouldn't it make more sense to have "gound" or "common" connection in circuits on + rather than the - pole?
 

wayneh

Joined Sep 9, 2010
17,496
It's not about making sense, it's a choice of convention so that we all use the same approach without having to state it all the time.

It's purely convention that we usually call the lowest common voltage in a circuit, "ground".
 

MrChips

Joined Oct 2, 2009
30,720
Purely convention.
When transistors were first available and applied, the PNP-type transistor was more common.
It was common practice to consider the +VE side of the battery as GROUND.

Also convention and convenience.
There are automotive systems that use -VE battery as GROUND while others use +VE.

There are high voltage supplies that use +VE or -VE as GROUND.

It has nothing to do with charge carrier flow.
 
Last edited:

crutschow

Joined Mar 14, 2008
34,286
The negative of the power supply is typically called common or ground, as noted by others, but there are some exceptions. Notable is early versions of ECL (emitter-coupled-logic). Using positive for ground minimizes the effect of power supply deviations on the logic level as discussed here.
 

Stuntman

Joined Mar 28, 2011
222
The negative of the power supply is typically called common or ground, as noted by others, but there are some exceptions. Notable is early versions of ECL (emitter-coupled-logic). Using positive for ground minimizes the effect of power supply deviations on the logic level as discussed here.
Need I mention that many cars around the 50's and prior had +6V "Grounds".

If you read on this site's textbook about the origins of electricity, you find that the convention was derived by interpreting observations of statically charged materials using preconceived notions of physics. They just happened to have their conjecture backwards.
 

MrChips

Joined Oct 2, 2009
30,720
Don't become obsessed with the direction of current flow or the charge of an electron.
Who says that an electron is negatively charge?
Why is the Arctic at the North Pole and upwards?
It is all relative and a matter of established convention.
 

MaxHeadRoom

Joined Jul 18, 2013
28,622
If you read on this site's textbook about the origins of electricity, you find that the convention was derived by interpreting observations of statically charged materials using preconceived notions of physics. They just happened to have their conjecture backwards.
Wasn't Benjamin Franklin the prime offender? :)
Max.
 

wayneh

Joined Sep 9, 2010
17,496
In grade school, the teacher once told us that the planets went around the sun in a clockwise direction. I asked, from which vantage point? The teacher claimed it didn't matter. End result - I spent some time in the principal's office.
 

Stuntman

Joined Mar 28, 2011
222
Wasn't Benjamin Franklin the prime offender? :)
Max.
Why yes he was.

Here is a snippet from the article for the OP that may clear the "why."

The result of an imbalance of this "fluid" (electrons) between objects is called static electricity. It is called "static" because the displaced electrons tend to remain stationary after being moved from one insulating material to another. In the case of wax and wool, it was determined through further experimentation that electrons in the wool actually transferred to the atoms in the wax, which is exactly opposite of Franklin's conjecture! In honor of Franklin's designation of the wax's charge being "negative" and the wool's charge being "positive," electrons are said to have a "negative" charging influence. Thus, an object whose atoms have received a surplus of electrons is said to be negatively charged, while an object whose atoms are lacking electrons is said to be positively charged, as confusing as these designations may seem. By the time the true nature of electric "fluid" was discovered, Franklin's nomenclature of electric charge was too well established to be easily changed, and so it remains to this day.
 

studiot

Joined Nov 9, 2007
4,998
If the forum info is to be believed zapp0 was last seen yesterday at 4.27pm.

Hopefully zapp0 will be back at some point.

Most of the time it does not matter whether you choose positive or negative as your reference, or even somewhere inbetween that we call zero, just so long as you are consistent.
And of course alternating voltage do not have positive and negative anyway.

There are some circuits where it does make a difference, however.

A good example would be galvanic protection circuits as widely used in industry, where the metal object to be protected is made positive or negative depending upon whether anodic or cathodic protection is employed.

The change in automobiles from positive earth to negative earth allegedly leads to less corrosion at the battery terminals.
 
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