why the current equal in this case?

Question

In a paralled circuit, why would the sum of thecurrent passing through (let say) 3 resistors is the same as the current entering and leaving the source?

**Isn't there is the same amount of current at all points of circuit**

Please help

Answer 1

No. In a parallel circuit the current splits up to take the different paths in proportion to their opposition to current flow.

Answer 2

Kirchoff's Current Law states that the curent entering a node (junction between two wires or devices) must equal the current leaving the node.

If the node (battery terminal) has two or more resistors attached to it in parallel, the current will divide, just like the water in a river divides to go around a rock that is placed in it. Some water goes to one side, some on the other. The sum of the two water currents equals the total water flow.

And, just like the water, the current re-unites when it passes through the parallel paths and comes together at another node. The total current (water OR electrons) remains the same.

The current entering the battery is the same as the current leaving the battery. But the current is not the same at all points within the circuit. Each parallel path has some current in it. But unless they are al of equal resistance, they do not have equal amounts of current flowing through them.

Devices in parallel have the same VOLTAGE across them. The smallest resistance will carry the largest current, and the largest resistance will carry the smallest current. This is in accordance with Ohm's Law.

20 NOV 06, 2241 hrs, GMT.

Answer 3

in a parallel circuit the voltage on the (say) 2 components is the same) and the current split up proportionally between the loads. if you do some sums with ohms law you will find that the resistor with the least resistance take more current and the resistor with the greater resistance takes more current, (which kind of makes sense)
In series it works in the opposite way the voltage splits up over the load and the current is a constant 'fowing' through the resistances.

(back to your question wandered off a bit)

the current is proportional to the power in the circuit, if you plug in a hoover 10A (not that I ever do!)and then a TV 5A and a computer 5A. The current flowing from the start of the circuit will be 20A the current will then split up between the loads and return back to 20A on the other side.

simply put, what goes in must come out.

the current entering a junction must equal the current leaving a junction

Kirchoffs law

http://en.wikipedia.org/wiki/Kirchhoff%27s_circuit_laws

Answer 4

Imagine the wire as a water pipe and the current as the amount of water passing though. If you have a pipe split into a small pipe and a big one and then rejoin, the same amount of water will not pass through the small one as does the big one. More water (current) will flow through the big pipe because that is easier (there is less resistance).

The amount of water that enters the two pipes is the same amount of water that leaves the pipes. It has nowhere else to go. Therefore "sum of the current passing through is the same as the current entering and leaving the source".

Answer 5

**Isn't there is the same amount of current at all points of circuit**

No.

in a paralleled circuit, there is the same amount of voltage across all of the paralleled parts. The current is dependent on the resistance of the branches.

look at http://www.ndt-ed.org/EducationResources/HighSchool/Electricity/parallelcircuit.htm

The resistor on the left will have a different current than the resistor on the right, if they have different amounts of Ohms.

To calc the amps in a parallel circuit, see http://answers.yahoo.com/question/index;_ylt=AvsO4yv3Sm2K2IotdbNWmXzsy6IX?qid=20061117141119AATjQb8

Answer 6

Kirchoff's law

Answer 7

problematic issue. look into with yahoo. just that might help!