What is the different between charge and current?

[zahrein]

What is the different between charge and current? Guyz i need to know the flow of these two elements,is it the same?


Can u describe the meaning of potential difference in a battery as well ?

 

[samcheetah]

current is the flow of charge. and potential difference is the difference of potential between two points.

go to http://www.amasci.com/miscon/whatdef.html to clear out some misconceptions about these terms

 

[samcheetah]

some more links

http://www.amasci.com/elect/charge1.html
http://www.amasci.com/miscon/voltage.html
http://amasci.com/miscon/whatis.html

just surf over the pages at this site and u will find all that u need

 

[Regnum]

i need to know the flow of these two elements,is it the same

It's a very common mistake. Current doesn't flow; current IS the flow.

Charge makes reference to some electrons amount. In SI system, charge unit is Coulomb, where 1 Coulomb = 6.2*10^18 electrons.

Current refers the electrons flow. In SI system, current unit is Ampere, where 1 Ampere = 1 Coulomb / Second.

 

[korek]

Current is a change of charge in time (time derivative)

 

[uladz55]

Charge is the quantity of elementary (unit) charges .
Current is the flow of charges per time unit.

Every charge create electric (electromagnetic for moving charge) field.
To move another charge in this field u need to change energy.
The characteristic of this energy changing is electric potential (or potential difference).
This is valid for battery.

About battery pls reference to

http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/electrochem.html

 

[cherrytart]

capacitance is the bucket
charge is the water in the bucket
current is the flow of water
voltage is the depth of the water

 

[taring77]

some links for you to expand your knowledge

h**p://www.victorianweb.org/science/maxwell.html
h**p://www.amasci.com/miscon/curstat2.html

enjoy

 

[smyback]

Cherrytart wrote:

capacitance is the bucket
charge is the water in the bucket
current is the flow of water
voltage is the depth of the water

Yes, charge is the volume of water in the bucket (ie. using your analogy, charge is the water!), but voltage is the -pressure- of the water.

Extending your analogy, a conductor is a pipe, and resistance is an obstruction in the pipe.


Another analogy for the capacitor:
---------------------------------------
An capacitor is a spring-loaded obstruction in-line with the pipe. When the water pressure is applied to it, the energy is NOT LOST but compresses the spring, moving the obstruction forward. When the water pressure drops, the spring moves the obstruction back again. This explains how a capacitor stores energy when the pressure increases, and releases it when the pressure decreases, and prevents the flow of unidirectional (DC) current.

 

[dinolin]

Cherrytart wrote:

capacitance is the bucket
charge is the water in the bucket
current is the flow of water
voltage is the depth of the water

Yes, charge is the volume of water in the bucket (ie. using your analogy, charge is the water!), but voltage is the -pressure- of the water.

Extending your analogy, a conductor is a pipe, and resistance is an obstruction in the pipe.

OK.... R C is ok ....
now L ?

 

[cherrytart]

L is a poser, the best analogy I can come up with is the mass of a turbine in the water flow. Which isn't very intuitive.

Sometimes you just gotta do the merciful thing and shoot your poor overworked metaphor.

 

[djalli]

no one mentioned it that voltage is indeed potential difference but the voltage actually is force. Energy lays on charge. Current does not flow. Current is flow of charge. The force to make this flow happening is voltage.

 

[delay]

If there is charge stored on two points A and B and it is different in magnitude then then there is a "potential" or propensity to flow, i.e., there is a potential difference between the two points also called voltage. Given a voltage difference between two places, current can result between the two points provided there is some impedance or conductive path. Current is always a result of voltage difference.

delay (delayed by technology)

 

[iloduba]

Charge is an elementary ionic unit present in every metals and could be accounted for in some other materials which are non-matels and hence, determine the conductivity of every element presently known. While current is the time rate of flow of charges through a mediu( conductive materials).

 

[checkmate]

Many have just interpreted current as the flow of charges per unit time.
The more accurate (and microscopic) description of current is characterised by I=nevA, where
n is the number density of electrons in the conductor
e is the elementary charge
v is the drift velocity, or net movement of positive charges in the perceived direction of current flow. (Note that this is the scalar component of the flow of electrons in the opposite direction)
A is the cross sectional area of the conductor perpendicular to the perceived flow of positive charges.
The difference is important when you have to calculate the capacitive components of some structures.
You want a universally correct definition for current? I think it's an SI unit

 

[coolchip]

If current is the flow of charges(electrons in a conductor) then why isn't speed of current = speed of flow of charges(i.e. drift velocity) ?

 

[kidiotb]

Charge flows from a higher potential to lower potential region and this gives current!!.For coolchip's question the answer lies in this link.
**broken link removed**

There it finally says,for a given conductor:
I=nAvQ;
where
where n is the number of electrons per cubic metre
A is the cross sectional area of the wire
v is the drift velocity of the electrons
Q is the charge of an electron

 

[the_penetrator]

I = C * (dV/dt)

Q = C*V

I = dQ/dt

if i recall my high-school math.

 

[dreamcard]

current is the flow of charge and i=dQ/dt.