what is the kirchoffs current law.?

Question

current theorem

Answer 1

Kirchoff's current law:

This law is also called Kirchhoff's first law, Kirchhoff's point rule, Kirchhoff's junction rule, and Kirchhoff's first rule.

The principle of conservation of electric charge implies that:

At any point in an electrical circuit where charge density is not changing in time, the sum of currents flowing towards that point is equal to the sum of currents flowing away from that point.
A charge density changing in time would mean the accumulation of a net positive or negative charge, which typically cannot happen to any significant degree because of the strength of electrostatic forces: the charge buildup would cause repulsive forces to disperse the charges.

However, a charge build up can occur in a capacitor, where the charge is typically spread over wide parallel plates, with a physical break in the circuit that prevents the positive and negative charge accumulations over the two plates from coming together and cancelling. In this case, the sum of the currents flowing into one plate of the capacitor is not zero, but rather is equal to the rate of charge accumulation. However, if the displacement current dD/dt is included, Kirchhoff's current law once again holds. (This is only required if one wants to apply the current law within the capacitor. In circuit analyses, however, the capacitor as a whole is typically treated as a unit, in which case the ordinary current law holds since the net charge is always zero.)

Kirchoffs voltage law:

This law is also called Kirchhoff's second law, Kirchhoff's loop rule, and Kirchhoff's second rule. It is a consequence of the principle of conservation of energy.

The principle of conservation of energy implies that:

The directed sum of the electrical potential differences around a circuit must be zero.
(Otherwise, it would be possible to build a perpetual motion machine that passed a current in a circle around the circuit.)

This law has a subtlety in its interpretation, because in the presence of a changing magnetic field the electric field is not conservative and it cannot therefore define a pure scalar potential—the line integral of the electric field around the circuit is not zero. Equivalently, energy is being transferred from the magnetic field to the current (or vice versa). In order to "fix" Kirchhoff's voltage law for this case, an effective potential drop, or electromotive force (emf), is associated with the inductance of the circuit, exactly equal to the amount by which the line integral of the electric field is not zero by Faraday's law of induction.

Answer 2

Kirchhoff's Current Law :
This fundamental law results from the conservation of charge. It applies to a junction or node in a circuit -- a point in the circuit where charge has several possible paths to travel.
IF we consider IA is the only current flowing into the node and there are three paths for current to leave the node, and these current are represented by IB, IC, and ID.

Once charge has entered into the node, it has no place to go except to leave (this is known as conservation of charge). The total charge flowing into a node must be the same as the the total charge flowing out of the node. So,

IB + IC + ID = IA
Bringing everything to the left side of the above equation, we get
(IB + IC + ID) - IA = 0
Then, the sum of all the currents is zero. This can be generalized as follows :
Summation(I)=0

Note the convention we have chosen here: current flowing into the node are taken to be negative, and currents flowing out of the node are positive. It should not really matter which you choose to be the positive or negative current, as long as you stay consistent. However, it may be a good idea to find out the convention used in your class.

You must visit following website for better understanding:
http://www.facstaff.bucknell.edu/mastascu/elessonsHTML/Basic/Basic4Ki.html

Answer 3

This law is also called Kirchhoff's first law, Kirchhoff's point rule, Kirchhoff's junction rule, and Kirchhoff's first rule.

The principle of conservation of electric charge implies that:

At any point in an electrical circuit where charge density is not changing in time, the sum of currents flowing towards that point is equal to the sum of currents flowing away from that point.
A charge density changing in time would mean the accumulation of a net positive or negative charge, which typically cannot happen to any significant degree because of the strength of electrostatic forces: the charge buildup would cause repulsive forces to disperse the charges.

However, a charge build up can occur in a capacitor, where the charge is typically spread over wide parallel plates, with a physical break in the circuit that prevents the positive and negative charge accumulations over the two plates from coming together and cancelling. In this case, the sum of the currents flowing into one plate of the capacitor is not zero, but rather is equal to the rate of charge accumulation. However, if the displacement current dD/dt is included, Kirchhoff's current law once again holds. (This is only required if one wants to apply the current law within the capacitor. In circuit analyses, however, the capacitor as a whole is typically treated as a unit, in which case the ordinary current law holds since the net charge is always zero.)

More technically, Kirchhoff's current law can be found by taking the divergence of Ampere's law with Maxwell's correction and combining with Gauss's law, yielding:


This is simply the charge conservation equation (in integral form, it says that the current flowing out of a closed surface is equal to the rate of loss of charge within the enclosed volume). Kirchhoff's current law is equivalent to the statement that the divergence of the current is zero, true for time-invariant ρ, or always true if the displacement current is included with J.

Answer 4

See the source below for more details (including a picture that will probably help).

Kirchoff's Current Law (KCL) is a specialized form of a much more general set of "laws" that state that incoming flow must equal outgoing flow as a consequence of conservation.

In the case of a circuit, at any junction (i.e., a spot where wires come together), if a positive magnitude is assigned to all of the currents going (for example) in to the junction and a negative magnitude is assigned to all of the currents going out of the junction, then the sum of all of the currents should be zero.

Put another way, the sum of the currents out of a junction must equal the sum of the currents into the junction.

Now, this may be confusing, but when people refer to using "node voltages" to solve a circuits problem, they are using KCL. This method uses the voltages at every junction in a circuit to calculate the currents into and out of each of those junctions. Setting up equations relating the voltages at every junction gives a linear system that can be solved for all of the voltages in the circuit.

Answer 5

Check Kirchhof's Circuit Laws in Wikipedia. Very well explained. The current law can be more easily understood if you consider current flowing to the junction as +ve and flowing out as -ve. The voltage law is simply all the voltages in the circuit is +ve (only the series ones add up) and that of the source is -ve. If more than one source is connected in series they add up in the -ve.

Answer 6

the law state that total curreant meating at a node is allways zero.
we can also say that the curret coming to a point is equal to the current leavingto the point

Answer 7

kirchoff's current law is also known as kirchoff's first law.It states that"the algebraic sum of the currents entering the junction is equal to the sum of currents leaving the junction.

Answer 8

At any point on a circuit

Σ Currents in = Σ Currents out

Answer 9

This fundamental law results from the conservation of charge. It applies to a junction or node in a circuit -- a point in the circuit where charge has several possible paths to travel.

http://www.physics.uoguelph.ca/tutorials/ohm/Q.ohm.KCL.html

Answer 10

kirchoffs current law : algebric sum of all current entering at a node is equal to algebric sum of current leaving .

https://www.electrikals.com/