What do - and + symbols mean in relation to electricity?

[electricDesire]

Hello!
what do these signs - &+ mean, exactly? how do they relate to electricty? do they have something to do with directions?
thank you!

 

[animagus]

Re: - , +

+,- signs are related with only DC supply. Conventional flow of electric current, DC current of course, is from + terminal of power source to - terminal, however the flow of electrons is from - terminal to + terminal.

 

[electricDesire]

Re: - , +

If i have a battery and a resistance, the current will flow from - to + in the batterey to the resistance and this conflicts the facts u outlined, however, wut is really the current if so-called current moves against the direction of electrons?

 

[A.Anand Srinivasan]

Re: - , +

you would often see voltage sources being modelled as a capacitor because it only sources current but ideally it doesn't have current inside it flowing from - to +....

 

[animagus]

Re: - , +

Well actually electron flow constitutes the current flow: now +, _ signs are mentioned as per the convenience so as to be able to solve the electrical circuits and for network analysis, and it is nothing wrong in considering the flow of current to be going from - to + terminal of battery, but conventionally i.e. before the concept of electron flow was discovered it was assumed that current flows from + terminal of battery to - terminal of battery and that is what still followed just for the sake of simplicity.
With respect.
Animagus

 

[hakeen]

Re: - , +

Where did you see these signs? Was it on a rating label (like power table of a motor)?

Or was it in a circuit diagram?

Pls explain more..

 

[illucius]

- , +

It should be on a lot of things. All batteries have them to label which side is positive and which is negative. Circuit diagram voltage supplies use them to indicate the positive and negative sides to indicate current flow or voltage levels.

 

[aersoy]

- , +

it is about voltage polarity but never forget that there is no absolute voltage it dependes on your reference point ( the point where the voltage is assumed to be 0 )

 

[cai2]

Re: - , +

when a current is flowing through an element assuming you enter first in the positive side,say +,-; it means voltage drop, otherwise, voltage rise....