#### Transcript of Kirchhoff's Law

Kirchhoff's Current Law

What is Kirchhoff's Law?

In 1845, German physicist Gustav Kirchhoff first described two laws that became central to electrical engineering. The laws were generalized from the work of Georg Ohm.

also known as Kirchhoff's Junction Law and Kirchhoff's First Law, defines the way that electrical current is distributed when it crosses through a junction - a point where three or more conductors meet.

Since current is the

flow of electrons through

a conductor, it cannot build up at a

junction, meaning that current is

conserved: what comes in must come out.

When performing calculations, current flowing into and out of the junction typically have opposite signs.

Kirchhoff's Voltage Law

Kirchhoff's Voltage Law describes the distribution of voltage within a loop, or closed conducting path, of an electrical circuit . Specifically, Kirchhoff's Voltage Law states that:

The algebraic sum of the voltage (potential) differences in any loop must equal zero.

Example

Given the circuit below with 3 A of current

running through the 4 Ω resistor as indicated in the diagram to the right. Determine…

a. the current through each of the other resistors,

b. the voltage of the battery on the left, and

c. the power delivered to the circuit by

the battery on the right.

Current Law

I in = I out

**Kirchhoff's Law**

Specifically, the law states that:

The algebraic sum of currents in a

network of conductors meeting at a point is zero

This allows Kirchhoff's Current Law to be restated as:

The sum of current into a junction equals

the sum of current out of the junction.

Voltage Law

v 1 + v 2 + v 3 + v 4 = 0

Full transcript