*e*on electron is negative and has magnitude of 1.602 x 10

^{-19}and the proton carries the same magnitude as electron but positive charge.

## Electric Charge

Every electrical phenomenon is based on the basic concept of electric charge.

*Electric charge*is also the most fundamental quantity of electric circuit. The electric charge's meaning is shown below :Charge is an atomic particles in electrical system, measured in coulombs (C)

Some points we need to take note are shown below :

- Large unit of charges is Coulomb. For every 1 C of charge contains 1/(1.602 x 10
^{-19}) = 6.24 x 10^{18}electrons. - From experiment observatory, the only charges that happen in nature are integral multiplies of electronic charge
*e*= -1.602 x 10^{-19}C. - From "
*Law of Conservation of Charge*" states that charge can not be created or destroyed, it can only be transferred from a point to another where it can be converted to another energy form.

This circuit element is useful for calculating electric power.For the conventional purpose, the current flow will be determined by positive charge flow direction even the electron itself (negative charge) moving in the opposite direction. The current flow direction can be seen in Figure.(1).

## Electric Current

Before moving to the next part, let us take a look a short explanation below :

Electric current is the change of charge in a period of time, measured in amperes (A)

In the mathematic equation, the relationship between current

*i*, charge*q*, and time*t*is expressed as :
i = current (A)

and

**1 ampere = 1 coulomb/second**

We can obtain the transferred charge between time

*t*and_{o}*t*using integral for both sides. Equation.(2).(2) |

Looking back to Equation.(1), the current do not need to be in constant-value function. For further explanation, we will find there will be a variation changes of charge. There are two types of current.

After learning about electric current, you need to learn about electrical voltage.

If current has constant value over time or its value does not change with time, we call it

*direct current*(dc) as we can see in Figure.(2).The symbol of constant current isa direct current (dc) is a current which has constant value with time changing.

*I*.

A changing current over time is represented by

An alternating current (ac) is a current that varries sinusoidally in a time period.

*i*symbol. This time-changing current is represented by alternating current (ac). The alternating current has the sinusoidal waveform shown in Figure.(3).An alternating current (ac) is a current that varries sinusoidally in a time period.

Figure 3. Alternating current waveform |

For reminder, the current direction will refer to positive charge direction of flow.

## Electric Current Example

**1. How many charges in 4.600 electrons?**

__Solution :__
Every electron has -1.602 x 10

^{-19}C. Thus 4.600 electrons will have -1.602 x 10^{-19}x 4.600 = -7.369 x 10^{-16 }C.**2.Total charge entering one terminal is q = 5t sin4πt mC. Calculate the current at t = 0.5 s.**

__Solution :__**3.Calculate the total charge entering a terminal for a period time from t =1 s to t = 2 s if the current is i = (3**

*t*^{2}-*t*) A.

__Solution :__Have you understood what are electric current?

Don't forget to share and subscribe!

Happy learning!

*Reference: Fundamentals of electric circuits by Charles K. Alexander and Matthew N. O. Sadiku*

Untuk Bahasa Indonesia dan penjelasan sederhana baca Definisi Muatan dan Arus Listrik.

## Post a Comment

## Post a Comment