What Does Current Mean

Are you in need of information on the electrical current? Then, to be well informed, please read through this article on What Does Current Mean.

This article is equipped with lots of information on all you need to know about the current – specifically electrical current.

It also gives reference to standard laws in electrical engineering. Plus, you get to see some mathematical expressions and practical applications.

To make your understanding easier, I will start with an overview. Immediately after that, I will explain the concept of current flow in a circuit – This concept will be contained in how it works section.

In the next section, I will talk about the types of electrical current and their features. After that, I will discuss Ohm’s law, where I will acknowledge the mathematical aspect of Ohm’s law.

Coming up after this will be the steady-state and transient currents. The relationship between voltage, current, and power follows next.

Then, you will see the effect of current on conductors. After that will the pros and cons of electric current.

Lastly, I will give answers to some frequently asked questions on electric current and my final thought.

Meaning Of Current; Overview

The term current is applicable in various aspects of life. However, these multiple aspects have different definitions of current depending on their application. Mostly, we have ocean current, lightning current, electric current, etc.

Ocean current refers to a body of water moving in a definite direction through a surrounding body of water in which there is less movement. In a body of water, the current always has a greater amount of pressure than the normal flow of water in the water body.

In the aspect of lightning current, it is related to electrical current. This is because both deal with charged particles. Lightning is often related to thunder clouds.

Hence, a lightning current is a transient action that involves the visible discharge of electric charges in the cloud. It occurs when a cloud region carries an excess electrical charge (positive or negative), which is enough to break air resistance.

Specifically, this article will concentrate on electric current. Electricity is very common in our world today. It is used in virtually all home, office, and industrial equipment.

Therefore, Electric Current is the rate at which electrical charges flow through a conductor in a closed electrical path called a circuit. The continuous flow of this electric current is known as Electricity.

Specifically, the amount of current in an electric circuit is dependent on the flow of charges at a particular time.

Mathematically

Q = I * t.

Hence, I=Q/t

Where,

“Q” is the quantity of charges in coulombs (C).
“t” is the time/duration, seconds (s) at which the current flows.
“I” is the current flow.

The SI unit of current is Amperes (A, Amps). It is measured with an instrument called an Ammeter. However, a smaller current can be measured with a milliammeter or galvanometer.

What Does Current Mean; How It Works

The existence of electric current can only be noticed in a closed electrical circuit. This electrical circuit is a closed path made by conductors, the electrical source, and the load.

Ideally, the current in an electrical circuit moves from the positive terminal through the circuit to the negative terminal of the source (battery). This movement involves a positive charge. However, electrons would move in an opposite direction through the wires.

Furthermore, the charge-carrying particles in an electrical circuit are mobile electrons. Hence, the direction of the positive charge particles determines the direction of the electric current. Consequently, if this path is broken, the electric current stops flowing.

During this flow, the electric current is not lost. Every positive charge leaving the position terminal of a source flows back to the same source through the negative terminal even when it encounters a node.

This is made clear in Kirchoff’s Current Law (KCL). The KCL states that the “total current or charge that enters a node or junction equates to the total current leaving the junction”. Hence, no charge is lost as there is no other place to go but to leave the node and travel back to the source.

What Does Current Mean; Types Of Current And Their Features

In the context of electric circuits, there are two types of current. These are the Alternating Current (AC) and Direct Current (DC).

Direct Current (DC)

The Direct Current is a uni-directional electric current. Thus, its flow of charge is always in one direction. Therefore, it is the current that flows in all electronic circuits.

Direct current is derived from batteries (rechargeable or non-rechargeable), rectifiers, regulators, DC generators, etc. They appear like a straight line that does not vary.

Features Of Direct Current

They are uni-directional. That is, they move in one direction.
Also, they are derived from batteries.
Furthermore, when you measure it with an oscilloscope, you see a straight line on the screen.

Alternating Current (AC)

Alternating Current is an electrical current in which its flow of particles reveres within regular intervals. Its representation on an oscilloscope is with a sinusoidal wave. Hence, it has both positive and negative half-cycles.

Devices that produce AC are alternators, inverters, transformers, etc. They are useful in almost all electrical appliances in our homes, offices, and industries.

Features Of Alternating Current

Source

AC generators or alternators are the major sources of alternating currents. These devices produce AC using Electromagnetic Induction. Electromagnetic Induction is the process of placing a conductor in a varying magnetic field to produce voltage or electromotive force (EMF).

Transformers do not generate AC; rather, they either step up or down some of its parameters. The inverters, on the other hand, convert DC to AC.

Amplitude

This is the highest displacement between the AC sinusoidal wave and the horizontal axis on a graph. Its measurement can be a peak, peak-to-peak, average, or RMS (root mean square).

Frequency

The frequency is the number of cycles the sine wave makes in one second. Its SI unit is Hertz. Thus, the most commonly known is 60Hz.

Other features of AC are phase angle, period, power factor, etc.

Ohm’s Law

The operation of the electric current in a circuit will be incomplete if we do not analyze Ohm’s law. This law shows the relationship between voltage and current in a circuit.

Therefore, Ohm’s Law states that the current passing through a conductor between two points is directly proportional to the voltage between these points. The condition of this law is that all other quantities remain constant. Hence, the voltage varies directly with the current.

Mathematically,

For DC, V= I * R

Therefore, I = V/R

For AC, V = I * Z

Hence, I = V/Z

Where
V = Voltage across the conductor.
I = current flowing through the conductor.
R = resistance of the conductor.
Z = impedance of the conductor (applicable to AC).

Voltage is the potential difference across a conductor. Its SI unit is volts. You measure voltage in a circuit using a voltmeter.

Resistance is the total opposition a current experiences in a DC circuit. Its SI unit is Ohms. You use an Ohmmeter to measure resistance.

This resistance could be affected by physical quantities like the length, cross-sectional area, and temperature of the conductor. However, without resistance, the current can not flow through a conductor.

Impedance is the total opposition a current experiences in an AC circuit. Just like resistance, its SI unit is Ohms. It is the vector sum of resistance and reactance.

The reactance in an AC circuit could either be inductive, capacitive, or both. More so, Induction reactance is the opposition to the flow of current due to the circuit’s inductance. Also, the capacitive reactance is the current opposition experiences due to the capacitance of the circuit.

Steady-State Current Vs Transient Current

When the current flowing in a circuit does not change with time, the current flowing in this circuit is a steady-state current. This steady-state current flows in a functional circuit, whether AC or DC.

In a DC circuit, the current flow without any sudden change, whether an increase or decrease in its magnitude. Also, in an AC circuit, the current flows in both half cycles periodically without any sudden change.

On the other hand, a transient current is a fault current that flows in a circuit. An aperiodic current occurs due to an electromagnetic disturbance like a lightning stroke. Also, it is hazardous, and it flows in a circuit for a very short time.

Graphically, the transient current is an exponential quantity concerning time. Hence, its increase and decrease are non-linear. Furthermore, the high level of current that occurs immediately after the transient fault is known as sub-transient current.

Mathematically, you can analyze the transient circuits using two methods. The first is analyzing it as a second-order differential equation. Another method is Laplace transform.

Relationship Between Power, Voltage, And Current

Let us use our electric bulb as an instance. What we see on our bulbs as illumination is voltage. At the same time, a current flow through the filament of that bulb.

Consequently, the bulb draws wattage. That means these three quantities are related.

In a DC circuit, there is only one type of power. This power is the product of current and voltage. Therefore, its SI unit is watts.

Mathematically,

P = V * I

where,

P = is the electrical power.

In an AC circuit, there are three types of power. These are real power, reactive power, and apparent power.

The real power is the product of voltage, current, and the power factor. However, the power factor is the cosine of the phase angle.

Mathematically,

P = V * I * cosθ

where.

θ = is the phase angle.

Real power is also called active power. Its SI unit is watts.

Also, the reactive power is the product of voltage, current, and sine of the phase angle. It is also called imaginary power.

Mathematically,

Q = V * I * sinθ

where,

Q = is the reactive power. Its SI unit is VAR (volt-ampere reactive).

Lastly, the apparent power is the product of voltage and current. Its SI unit is VA (volt-amperes).

Mathematically,

S = V * I

Where S is apparent power.

What Does Current Mean; Conductor, Semiconductor, And Insulator

Conductor

A conductor of electricity is any material that allows current to pass through it. These materials are mostly metals. This is because metals have a high level of impurities.

As a result, all wires and cables are products of metals. For example, most wires and cables are made from copper, aluminum, or steel.

Effects Of Current On A Conductor

Several effects occur on a conductor due to the current passing through it. These include:

  • Electromagnetic Field:

When an electric current passes through a conductor, an electromagnetic field is set up around the conductor. The direction of the magnetic field depends on the direction of current flow through the conductor. Hence, it creates a magnetic force.

Read more on the Laws Of Electromagnetism.

  • Rise In Temperature Of The Conductor:

The temperature of a conductor rises when an electric current passes through it. However, when you take the electric current off the conductor, its temperature gradually falls back to normal. The temperature rise is due to the resistance of the conductor.

  • Increase In The Length Of The Conductor:

The length of a conductor increases gradually as current passes through it. However, this is the reason power lines sag and joints become weak.

Insulator

An insulator is a material that does not allow current to pass through it. Instead, it has an infinite resistance that prevents current totally. These kinds of materials are used to make cables.

More so, the essence of these insulators in cables is to prevent current leakage. Also, to prevent humans and animals from potential hock if they mistakenly touch the cable. Materials used in making insulators are polyvinyl chloride, porcelain, and so on.

Semiconductors

Semiconductors are materials that possess some qualities of both conductors and insulators. Also, semiconductors allow only a controllable amount of current to plow through them. So, for example, if a semiconductor has a rating of 5A, only currents less than or equal to 5A can pass through it.

In a situation where the current passing through that conductor is higher, the semiconductor breaks down. Hence, it behaves like a conductor. In other words, it loses its qualities.

Semiconductors are mostly made from silicon, germanium, and gallium arsenide. Examples include diodes, transistors, thyristors, and so on.

What Does Current Mean; Pros And Cons

Pros

The benefits of electric current are too numerous. However, below are some of the benefits as applicable in different areas.

  • Entertainers use Electricity to make their shows lively. It is used to create stage effects, play musical instruments, etc.
  • Modern healthcare facilities can not operate without Electricity.
    Every modern means of transportation has an electrical system. This system supplies current to vital parts. Even the control.
  • Our modern communication system uses Electricity.
    Some kitchen appliances use Electricity. These include range hoods, refrigerators, blenders, coffee makers, etc.

Cons

  • Electricity could be expensive to use.
  • It could be hazardous when you use it wrongly.

What Does Current Mean; Frequently Asked Questions

1. Which is the best definition of electrical current?

Electrical current is that it is the amount of charge flowing in a wire per unit of time.

2. What are types of current?

The two main types of current are direct current and alternating current.

3. What type of current is used on homes?

The outlets in our home are alternating current. It has a frequency of 60Hz.

4. What is the difference between volt and amp?

Volt is the pressure that allows electrons to flow. However, the volt is the SI unit of voltage.
On the other hand, the amp is short for amperage. It is a measure of the volume of electrons.

5. What is the normal voltage in a house?

120 volts.
Practically, the actual voltage will be between 115 volts and 125 volts.

6. Can an outlet have too much load?

Plugging many electrical items into one outlet could be risky. It can go beyond just tripping a breaker. A fire outbreak could occur as a result.

7. Are batteries AC or DC?

Batteries produce DC.
Some devices in your house use DC. Devices like TV, computers, and DVD players. You could think they use AC because you plug them into an outlet. They have a system that converts AC to DC. A rectifier is the name of the system.

8. What is the difference between voltage and current?

Voltage is the potential difference between two points.
Current is the rate of flow of charges.

9. What kills, voltage or current?

It is current that kills, not voltage. At the same time, voltage drives current. The amperage is responsible for electric shock. Please note that both DC and AC are dangerous.

10. Are solar panels AC or DC?

Solar panels generate direct current (DC). However, an inverter is used to convert the DC to AC.

What Does Current Mean; Wrap Up

The movement of charged particles is what brings about electric current. Then, the continuous flow of electric current is Electricity. Electricity is vital to our daily lives.

However, I am sure this piece contains most if not all of all you need to know about current. It gives even the mathematical expressions that explain the current.

Also, the Laws which analyze the current have been discussed. Hence, this quenches your curiosity about electric current.

I hope you found this article helpful.

Hence, fill out the “Leave A Reply” form to share your thoughts.

Lastly, visit our Electricity & Renewables page for more guides like this.

Christian Jerome
Christian Jerome
Akan Christian writes for PowerVersity.com. He holds an HND in Electrical/Electronic Engineering. Christian enjoys reading, listening to solemn music, singing, and playing sports. For PowerVersity.com, Christian writes reviews, buying guides, and best-pick articles.

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