Potential gradient

Storyboard

A gradient is a vector that is constructed for a function that indicates the direction and inclination that the function presents at all points. In particular the gradient of the electric potential is equal to minus the electric field.

>Model

ID:(1568, 0)



Gradient of a function

Image

>Top


The gradient is a vector calculated for a function that points to a maximum / minimum close to the point in which it is being considered.

ID:(11555, 0)



Gradient in one dimension

Image

>Top


The gradient is a vector calculated for a function that points to a maximum / minimum close to the point in which it is being considered. In the case of a dimension this coincides with the slope of the curve:

ID:(11558, 0)



Gradient in two dimensions

Image

>Top


The gradient is a vector calculated for a function that points to a maximum / minimum close to the point in which it is being considered.

ID:(11605, 0)



Total variation

Image

>Top


The gradient is a vector calculated for a function that points to a maximum / minimum close to the point in which it is being considered.

ID:(11606, 0)



Variation of the electric potential in three dimensions

Equation

>Top, >Model


La variación total se puede estimar como la suma de las distintas variaciones.

$ d\varphi = \displaystyle\frac{\partial \varphi}{\partial x} dx + \displaystyle\frac{\partial \varphi}{\partial y} dy + \displaystyle\frac{\partial \varphi}{\partial z} dz $

ID:(11556, 0)



Gradient vector: the gradient

Image

>Top


The gradient is a vector calculated for a function that points to a maximum / minimum close to the point in which it is being considered.

ID:(11607, 0)



Gradient of the electric potential

Equation

>Top, >Model


We can construct a vector tangent to the field considering the variation

$ d\varphi = \displaystyle\frac{\partial \varphi}{\partial x} dx + \displaystyle\frac{\partial \varphi}{\partial y} dy + \displaystyle\frac{\partial \varphi}{\partial z} dz $



each component by itself assigning the corresponding versor:

$ \nabla \varphi = \hat{x}\displaystyle\frac{\partial \varphi}{\partial x} + \hat{y}\displaystyle\frac{\partial \varphi}{\partial y} + \hat{z}\displaystyle\frac{\partial \varphi}{\partial z}$

ID:(11559, 0)



Field as gradient of electric potential

Equation

>Top, >Model


Since the change in potential is

$ d\varphi = -\vec{E} \cdot d\vec{s} $



the gradient of the potential is

$ d\varphi = \displaystyle\frac{\partial \varphi}{\partial x} dx + \displaystyle\frac{\partial \varphi}{\partial y} dy + \displaystyle\frac{\partial \varphi}{\partial z} dz $



and the element of the path

d\vec{s} = \hat{x} dx + \hat{y} dy + \hat{z} dz

we have that the gradient of the potential is equal to minus the electric field

$ \vec{E} = -\nabla\varphi $

ID:(11557, 0)



0
Video

Video: Potential gradient