Druyd:Knowledge

Ohm's Law

Storyboard

If a field is applied to a load, a force is obtained. Such force applied along a path leads to potential energy. If it is expressed with an electric field, the potential energy per charge that we call electrical potential is obtained. The electric potential generates displacement of charges which implies that there is a flow that we call electric current. Its magnitude depends on the electrical potential and the resistance that the material in which the electrons that we will call the conductor are. The resulting law is the so-called Ohm's law.

>Model

ID:(815, 0)

Current by a conductor

Definition

ID:(7860, 0)

Resistance and heat

Image

ID:(11761, 0)

Ohm's Law

Description

When a field is applied to a charge, it generates a force. This force, when acting along a path, gives rise to potential energy. If this potential energy is expressed in terms of an electric field, it becomes the potential energy per unit charge, known as electric potential. The electric potential induces the movement of charges, creating a flow called electric current. The magnitude of this current depends on both the applied electric potential and the resistance of the material through which the charges move, commonly referred to as the conductor. The resulting relationship between electric potential, current, and resistance is described by the well-known Ohm's law.

Variables

Symbol

Text

Variable

Value

Units

Calculate

MKS Value

MKS Units

$a$

Acceleration of charge in the conductor

m/s^2

$\bar{v}$

v_m

Average speed of charges

m/s

$c$

Charge concentration

1/m^3

$L$

Conductor length

$I$

Current

$E$

Electric eield

V/m

$\Delta Q$

Load element

$v_{max}$

v_max

Maximum Speed

m/s

$\Delta\varphi$

Dphi

Potential difference

$R$

Resistance

Ohm

$\rho_e$

rho_e

Resistivity

Ohm m

$S$

Section of Conductors

m^2

$\tau$

tau

Time between collisions

$\Delta t$

Time elapsed

Calculations

Equation

Number

First, select the equation:

, then, select the variable:

Symbol

Equation

Solved

Translated

Calculations

Symbol

Equation

Solved

Translated

Variable

Given

Calculate

Target :

Equation

To be used

Equations

$ \Delta\varphi = R I $

Dphi = R * I

None

(ID 3214)

$ v_{max} =\displaystyle\frac{ e E }{ m_e } \tau $

v_max =( e * E/ m_e )* tau

(ID 3836)

$ I =\displaystyle\frac{ e ^2 E }{2 m_e } \tau c S $

I = e ^2* E * tau * c * S /(2* m_e )

(ID 3837)

$ E =\displaystyle\frac{ \Delta\varphi }{ L }$

E = Dphi / L

None

(ID 3838)

$ \Delta\varphi =\displaystyle\frac{2 m_e }{ e ^2 \tau c }\displaystyle\frac{ L }{ S } I $

Dphi =(2 * m_e /( e ^2* tau * c ))*( L / S )* I

(ID 3839)

$ \rho_e =\displaystyle\frac{2 m_e }{ e ^2 \tau c }$

rho_e =2* m_e /( e ^2* tau * c )

(ID 3840)

$ R = \rho_e \displaystyle\frac{ L }{ S }$

R = rho_e * L / S

(ID 3841)

$ a =\displaystyle\frac{ e E }{ m_e }$

a = e * E / m_e

None

(ID 3843)

$ I = e S c \bar{v} $

I = e * S * c * v_m

(ID 10400)

$ I =\displaystyle\frac{ \Delta Q }{ \Delta t }$

I = DQ / Dt

None

(ID 10401)

$ v_{max} = a \tau $

v_max = a * tau

(ID 16236)

$ \overline{v} =\displaystyle\frac{1}{2} v_{max} $

v_m = v_max / 2

(ID 16237)

Examples

Simulation of the resistance model

(ID 16003)

Current by a conductor

In summary, the application of a potential difference between the two ends of the \Delta\varphi conductor generates a current I that depends on the resistance R:

(ID 7860)

Resistance and heat

The heat makes the atoms oscillate with a greater amplitude, making it difficult for the electrons to advance:

(ID 11761)

Model

(ID 16002)

ID:(815, 0)