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Your Position: Home - Automobiles & Motorcycles - How do I start understanding electricity?

How do I start understanding electricity?

We use electricity every day for (nearly) everything. From charging our cell phone to enjoying a hot bath to watching our favorite sitcoms on TV – electricity is practically everywhere. However, most of us probably couldn’t clearly answer the question, “How does electricity work?“ 

In this article, we’ll give you a clear understanding of what electricity is along with some interesting facts, including how many watts your daily appliances need.  

How Does Electricity Work?

 

The concept of electricity itself is based on electron movement. When you force electrons to move in sync, they end up producing heat, which turns the wire they’re moving in into a magnet.  

Britannica describes electricity as a phenomenon associated with stationary or moving electric charges. Every electrical charge is a fundamental property of matter being borne by elementary particles. 

For electricity, this elementary particle is an electron that has a negative charge, which is carried to the next electron through the convention method. So, when we talk about how electricity works, it’s essentially the result of the accumulation or motion of a specific number of electrons. Moreover, electricity travels in a closed circuit for the electrons to move through it. 

Let’s explain this with the help of an example. 

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Imagine you flip a switch to turn on a light. What do you do? You basically close a circuit. By applying the same logic, when you flip a switch off, you open a circuit.  

Now, when you close a circuit, the flow of electricity from the electric wires powers through them through the light, and vice versa. Likewise, the same logic applies when you charge your phone, switch on your television, or operate any other appliance. 

Moreover, electricity takes different forms like water, coal, wind, solar, hydroelectricity, and nuclear. 

How Is Electricity Made and What Is It Made Of?

 

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Not many people are aware that electricity is actually a secondary energy source – something that you derive from the conversion of other primary sources of energy, such as natural gas, coal, nuclear power, oil, and so on. Interestingly, these primary sources of energy can be either renewable or nonrenewable, but electricity itself is neither. 

Electricity is made up of building blocks called atoms, which is why you need to understand how atoms, and most importantly, how electrons behave. 

Every atom has a nucleus that’s made up of protons and neutrons, while electrons are charged particles that revolve around the nucleus in shells. As protons have a positive charge and electrons have a negative charge, they attract each other. This keeps both the charges equal, which, in turn, keeps the atom balanced. So, the positive charge on the proton is equal to the negative charge of electrons. 

Neutrons have no electric charge, and as such, they don’t have an active role to play when it comes to balancing an atom. 

Understanding the Relationship Between Protons and Electrons

 

Electrons have a strong attraction to protons. But the electrons in the outermost shell don’t have as strong an attraction to protons when compared to the electrons in the immediate shells.  

The weakly-attracted electrons can be pushed out of the orbit, which in turn, causes them to shift from one atom to another. It’s these shifting electrons that are electricity. 

Electricity is made of electrons. But from a technical point of view, it’s the flow of electric charge as a form of electricity that creates an electrical current flow. 

To recap, the movement of a number of electrons creates magnetic fields, which kickstarts the formation of electric charges.  

Conductive materials that are used to carry the electric charge, such as a copper wire, have a negative charge flow of electrons. This helps conduct electricity by giving the flow of electrons a targeted direction, allowing them to move uniformly while simultaneously creating a positive charge known as an electrical current. 

To create electricity, you need to properly harness this flow of electric current and then direct it along with a conductive material. 

How Is Electricity Measured? In What Units? 

Measuring electricity and electrical units is an interconnected affair. You’ll understand what this means shortly. 

The first unit of electric current measurement under the international system of units is ampere or amp (A). It denotes the number of electrons (aka the electric current) that flows through an electrical circuit at a given point in time. 

Next is volt (V), which is the measurement of the force that pushes the electron through an electric circuit. This force is also known as the electric potential difference. When we determine the voltage, we’re calculating the potential for the energy to move. Basically, lower voltage equals lower force, and high voltage means higher force. 

To measure electricity, you also need to measure electrical resistance, which is expressed in ohms (Ω). As mentioned, copper wire is a conductive material, and since it has minimal resistance, it allows the easy flow of electrons. It’s also why copper is a good conductor of electricity, having a low ohm reading. 

So there you have it: You need ampere, volt, and ohm to measure electricity.  

As for the interconnection between the three concepts, one amp is equivalent to the amount of current produced by a force of 1 V that acts through the resistance of 1 ohm.  

Now read that again slowly, we know it’s a bit complicated.  

The discussion of how to measure electricity will remain incomplete if you don’t mention watts (W), which is a measurement of power. Named after the Scottish inventor, James Watt, this unit of measurement indicates the rate at which work is done.  

If you think about the light bulb (created by another famous inventor, Thomas Edison), you’ll realize how it shines brighter when you increase the electrical power supplied, which also translates to a higher wattage. A one-watt light bulb converts one joule of electric energy per second. 

When measuring electricity, the last unit you should know is the coulomb, which is the amount of charge flowing whenever the current is one ampere.  

In other words, 1 ampere = 1 coulomb/second 

Why Is Electricity So Important?

 

We’re pretty sure nobody would argue against the importance of electricity. Considering the inconvenience caused by even a short electric power outage, life without electricity is almost unthinkable. After all, this is an essential form of energy that we use throughout our lives, whether it’s heating, lighting, transportation, or entertainment. 

In fact, we need electrical energy for a greener, cleaner Earth

From rotating wind turbine blades to solar power to channeling steam to geothermal power plants, it would all come to a standstill in the absence of electricity. If you want to enjoy renewable sources of energy, you need to ensure a steady electricity supply. 

Where Does Energy Come From?

 

In the United States of America, the three main electricity generation sources are coal, petroleum, and natural gas. But this may differ depending on the part of the world you live in. For instance, hydropower is the main source of electricity in Canada, but in France, electricity is mostly sourced from nuclear energy. 

Luckily, the growing awareness for alternative sources of energy has led to houses and industries employing wind energy and solar energy. Nuclear power plants, biomass, and hydroelectric stations are also being used to produce electricity. 

To learn more about your electricity source, you can contact your energy supplier for more information. 

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Why Is Electricity Not an Energy Source?

 

If you recall how we described electricity earlier, you’ll realize it’s a way of transporting energy from one place to another. Therefore, electricity isn’t an energy source in itself but rather a secondary source of energy. 

Let’s discuss this with the help of wind power. 

It’s the flow of wind that helps to drive the turbines, which are connected to an electric generator that creates electricity. So, once the electricity is generated and transported, the energy gets converted to other forms of energy. It also stands true to the first law of thermodynamics that it cannot be created or destroyed. 

The potential energy stored in renewable and non-renewable sources of energy is converted to electricity, which then helps power electric devices, vehicles, and other things. 

Determining Electricity Usage

 

Knowing the total electric consumption by common home appliances is crucial. After all, the higher your electricity consumption, the more you have to pay. Below, we’ve made a list of the electricity usage for several common electronic devices. 

How Much Electricity Does a TV Use?

 

Typically, most TVs use between 120 to 170 watts, depending on the size of the device and the technology used.  

For instance, a 42-inch LCD uses 120 watts, while a 50-inch LCD uses 150 watts. But when you change the technology, a 42-inch plasma TV would need 220 watts to run, while a 50-inch plasma, 300 watts. 

How Much Electricity Does a Computer Use?

 

The electricity consumption range of a desktop computer is anywhere between about 200 watts, and again depending on the type of device you use, electricity consumption will differ. 

How Much Electricity Does a Light Bulb Use?

 

To find out the amount of electricity used by a light bulb, you’ll have to look at the watts on its packaging. You can have bulbs that are 100 watts as well as bulbs that are 60 watts. Moreover, while an LED light bulb needs 18 watts, fluorescent tubes need about 36 watts. 

How Much Electricity Does an Oven Use?

 

Ovens come in all shapes and sizes – some are designed for commercial kitchens while others are made for domestic use. On top of this, the dishes you cook involve different cooking temperatures and duration as well. 

It’s normal for ovens to use anywhere between 1,000-5,000 watts, with the general average being around 2,400 watts per hour – provided the usual cooking temperature stays between 300-425°F. 

How Much Electricity Does an Air-Conditioner (AC) Use?

 

Similar to ovens, ACs are also available in a variety of configurations. Several other factors also affect the overall electricity consumed – from the number of rooms in your home or apartment to the desired inside temperature to your insulation, and so on.  

Geography and season are also crucial here. Think about it: AC usage during the winter in New York will be different than AC usage during summertime in Palm Springs. 

To give you an idea, an average central air-conditioner unit uses anywhere between 3,000-5,000 watts of power during the hotter months of the year. 

How Much Electricity Does a Dryer Use?

 

The average clothes dryer uses 5,000 watts while the average washer uses anywhere from 500 watts (non-electric water heating) to 1,800 watts (with electric water heating). 

Do Dimmers Use Less Electricity?

 

Yes, dimmers ensure a lower consumption of energy.  

Modern dimmers use less electricity as opposed to older dimmers as the former uses a TRIAC switch that cuts off the electric supply several times per second.  

As a result, the total amount of power reaching the light bulb is reduced. This lowers the amount of light produced, which in turn uses less electricity. 

How Much Electricity Do I Use?

 

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The best way to determine the total amount of electricity consumed is to analyze your monthly electricity bills.  

Your electricity usage will differ with seasons, weather, and other factors. For example, months when you’re not home will have lower electricity consumption as opposed to months when you have guests over. 

You can also calculate your power consumption by using the following formula: 

Step 1: Calculate the watts of every device you use daily

 

You will find this on the packaging of every device. Here’s a list of everyday devices to get you started: 

  • Microwave: 750-1,100 watts

     

  • Dishwasher: 1,200-2,400 watts

     

  • Iron: 100-1,800 watts

     

  • Laptop: 50 watts

     

  • Coffee maker: 900-1,200 watts

     

Step 2: Convert the watts to kilowatts 

 

Every 1000W is equal to 1kW, so just apply this for your wattage. 

Step 3: Find out the kilowatts and monthly appliance usage

 

You’ll need three formulas for this: 

  1. Calculating Watts-Hours per Day

Device Wattage (watts) x Hours used per day = Watt-hours (Wh) per day 

  1. Converting Watt-Hours to Kilowatts

Device usage (Wh) / 1000 (Wh/kWh) = Device usage in kWh 

  1. Find Your Monthly Usage

Daily usage (kWh) x 30 (Days) = approximate monthly usage (kWh / Month) 

Step 4: Calculate the entire cost 

 

Monthly usage in kilowatt-hours (kWh) x Electric rate ($/kWh) = approximate cost per month 

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What Is the Average Household Electricity Usage?

 

In 2019, the average annual electricity consumption for a residential utility customer in the U.S. was 10,649 kWh, an average of nearly 877 kWh per month. 

In French households, the average electricity usage was considerably lower at 6,400 kWh per year, while China consumes about 1,300 kWh annually. 

Different regions have different average usage. Plus, other factors like house size, availability of electricity, and appliance standards also affect the numbers. 

Electricity Literally Makes Our Future Bright 

 

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Today, most of the devices we use and activities we engage in require electricity. From cooling off with a fan to talking on a phone to driving (hello, Tesla owners!), it’s become a significant part of our daily lives. 

Adopting renewable power sources as opposed to fossil fuel sources can ensure a brighter future for our Earth and reduce carbon dioxide emissions. Contact your energy supplier to switch to electricity from renewable energy sources like solar panels, biomass, and wind turbines. 

Brought to you by justenergy.com

All images licensed from Adobe Stock.
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Electricity Basics

When beginning to explore the world of electricity and electronics, it is vital to start by understanding the basics of voltage, current, and resistance. These are the three basic building blocks required to manipulate and utilize electricity. At first, these concepts can be difficult to understand because we cannot "see" them. One cannot see with the naked eye the energy flowing through a wire or the voltage of a battery sitting on a table. Even the lightning in the sky, while visible, is not truly the energy exchange happening from the clouds to the earth, but a reaction in the air to the energy passing through it. In order to detect this energy transfer, we must use measurement tools such as multimeters, spectrum analyzers, and oscilloscopes to visualize what is happening with the charge in a system. Fear not, however, this tutorial will give you the basic understanding of voltage, current, and resistance and how the three relate to each other.

Georg Ohm

Covered in this Tutorial

  • How electrical charge relates to voltage, current, and resistance.
  • What voltage, current, and resistance are.
  • What Ohm's Law is and how to use it to understand electricity.
  • A simple experiment to demonstrate these concepts.

Suggested Reading

  • What is Electricity
  • What is a Circuit?

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Electrical Charge

Electricity is the movement of electrons. Electrons create charge, which we can harness to do work. Your lightbulb, your stereo, your phone, etc., are all harnessing the movement of the electrons in order to do work. They all operate using the same basic power source: the movement of electrons.

The three basic principles for this tutorial can be explained using electrons, or more specifically, the charge they create:

  • Voltage is the difference in charge between two points.
  • Current is the rate at which charge is flowing.
  • Resistance is a material's tendency to resist the flow of charge (current).

So, when we talk about these values, we're really describing the movement of charge, and thus, the behavior of electrons. A circuit is a closed loop that allows charge to move from one place to another. Components in the circuit allow us to control this charge and use it to do work.

Georg Ohm was a Bavarian scientist who studied electricity. Ohm starts by describing a unit of resistance that is defined by current and voltage. So, let's start with voltage and go from there.

Voltage

We define voltage as the amount of potential energy between two points on a circuit. One point has more charge than another. This difference in charge between the two points is called voltage. It is measured in volts, which, technically, is the potential energy difference between two points that will impart one joule of energy per coulomb of charge that passes through it (don't panic if this makes no sense, all will be explained). The unit "volt" is named after the Italian physicist Alessandro Volta who invented what is considered the first chemical battery. Voltage is represented in equations and schematics by the letter "V".

When describing voltage, current, and resistance, a common analogy is a water tank. In this analogy, charge is represented by the water amount, voltage is represented by the water pressure, and current is represented by the water flow. So for this analogy, remember:

  • Water = Charge
  • Pressure = Voltage
  • Flow = Current

Consider a water tank at a certain height above the ground. At the bottom of this tank there is a hose.

The pressure at the end of the hose can represent voltage. The water in the tank represents charge. The more water in the tank, the higher the charge, the more pressure is measured at the end of the hose.

We can think of this tank as a battery, a place where we store a certain amount of energy and then release it. If we drain our tank a certain amount, the pressure created at the end of the hose goes down. We can think of this as decreasing voltage, like when a flashlight gets dimmer as the batteries run down. There is also a decrease in the amount of water that will flow through the hose. Less pressure means less water is flowing, which brings us to current.

Current

We can think of the amount of water flowing through the hose from the tank as current. The higher the pressure, the higher the flow, and vice-versa. With water, we would measure the volume of the water flowing through the hose over a certain period of time. With electricity, we measure the amount of charge flowing through the circuit over a period of time. Current is measured in Amperes (usually just referred to as "Amps"). An ampere is defined as 6.241*10^18 electrons (1 Coulomb) per second passing through a point in a circuit. Amps are represented in equations by the letter "I".

Let's say now that we have two tanks, each with a hose coming from the bottom. Each tank has the exact same amount of water, but the hose on one tank is narrower than the hose on the other.

We measure the same amount of pressure at the end of either hose, but when the water begins to flow, the flow rate of the water in the tank with the narrower hose will be less than the flow rate of the water in the tank with the wider hose. In electrical terms, the current through the narrower hose is less than the current through the wider hose. If we want the flow to be the same through both hoses, we have to increase the amount of water (charge) in the tank with the narrower hose.

This increases the pressure (voltage) at the end of the narrower hose, pushing more water through the tank. This is analogous to an increase in voltage that causes an increase in current.

Now we're starting to see the relationship between voltage and current. But there is a third factor to be considered here: the width of the hose. In this analogy, the width of the hose is the resistance. This means we need to add another term to our model:

  • Water = Charge (measured in Coulombs)
  • Pressure = Voltage (measured in Volts)
  • Flow = Current (measured in Amperes, or "Amps" for short)
  • Hose Width = Resistance

Resistance

Consider again our two water tanks, one with a narrow pipe and one with a wide pipe.

It stands to reason that we can't fit as much volume through a narrow pipe than a wider one at the same pressure. This is resistance. The narrow pipe "resists" the flow of water through it even though the water is at the same pressure as the tank with the wider pipe.

In electrical terms, this is represented by two circuits with equal voltages and different resistances. The circuit with the higher resistance will allow less charge to flow, meaning the circuit with higher resistance has less current flowing through it.

This brings us back to Georg Ohm. Ohm defines the unit of resistance of "1 Ohm" as the resistance between two points in a conductor where the application of 1 volt will push 1 ampere, or 6.241×10^18 electrons. This value is usually represented in schematics with the greek letter "Ω", which is called omega, and pronounced "ohm".

Ohm's Law

Combining the elements of voltage, current, and resistance, Ohm developed the formula:

Where

  • V = Voltage in volts
  • I = Current in amps
  • R = Resistance in ohms

This is called Ohm's law. Let's say, for example, that we have a circuit with the potential of 1 volt, a current of 1 amp, and resistance of 1 ohm. Using Ohm's Law we can say:

Let's say this represents our tank with a wide hose. The amount of water in the tank is defined as 1 volt and the "narrowness" (resistance to flow) of the hose is defined as 1 ohm. Using Ohms Law, this gives us a flow (current) of 1 amp.

Using this analogy, let's now look at the tank with the narrow hose. Because the hose is narrower, its resistance to flow is higher. Let's define this resistance as 2 ohms. The amount of water in the tank is the same as the other tank, so, using Ohm's Law, our equation for the tank with the narrow hose is

But what is the current? Because the resistance is greater, and the voltage is the same, this gives us a current value of 0.5 amps:

So, the current is lower in the tank with higher resistance. Now we can see that if we know two of the values for Ohm's law, we can solve for the third. Let's demonstrate this with an experiment.

An Ohm's Law Experiment

For this experiment, we want to use a 9 volt battery to power an LED. LEDs are fragile and can only have a certain amount of current flowing through them before they burn out. In the documentation for an LED, there will always be a "current rating". This is the maximum amount of current that can flow through the particular LED before it burns out.

Materials Required

In order to perform the experiments listed at the end of the tutorial, you will need:

  • A multimeter
  • A 9-Volt battery
  • A 560-Ohm resistor(or the next closest value)
  • An LED

NOTE: LEDs are what's known as a "non-ohmic" devices. This means that the equation for the current flowing through the LED itself is not as simple as V=IR. The LED introduces something called a "voltage drop" into the circuit, thus changing the amount of current running through it. However, in this experiment we are simply trying to protect the LED from over-current, so we will neglect the current characteristics of the LED and choose the resistor value using Ohm's Law in order to be sure that the current through the LED is safely under 20mA.

For this example, we have a 9 volt battery and a red LED with a current rating of 20 milliamps, or 0.020 amps. To be safe, we'd rather not drive the LED at its maximum current but rather its suggested current, which is listed on its datasheet as 18mA, or 0.018 amps. If we simply connect the LED directly to the battery, the values for Ohm's law look like this:

therefore:

and since we have no resistance yet:

Dividing by zero gives us infinite current! Well, not infinite in practice, but as much current as the battery can deliver. Since we do NOT want that much current flowing through our LED, we're going to need a resistor. Our circuit should look like this:

We can use Ohm's Law in the exact same way to determine the reistor value that will give us the desired current value:

therefore:

plugging in our values:

solving for resistance:

So, we need a resistor value of around 500 ohms to keep the current through the LED under the maximum current rating.

500 ohms is not a common value for off-the-shelf resistors, so this device uses a 560 ohm resistor in its place. Here's what our device looks like all put together.

Success! We've chosen a resistor value that is high enough to keep the current through the LED below its maximum rating, but low enough that the current is sufficient to keep the LED nice and bright.

This LED/current-limiting resistor example is a common occurrence in hobby electronics. You'll often need to use Ohm's Law to change the amount of current flowing through the circuit. Another example of this implementation is seen in the LilyPad LED boards.

With this setup, instead of having to choose the resistor for the LED, the resistor is already on-board with the LED so the current-limiting is accomplished without having to add a resistor by hand.

Current Limiting Before or After the LED?

To make things a little more complicated, you can place the current limiting resistor on either side of the LED, and it will work just the same!

Many folks learning electronics for the first time struggle with the idea that a current limiting resistor can live on either side of the LED and the circuit will still function as usual.

Imagine a river in a continuous loop, an infinite, circular, flowing river. If we were to place a dam in it, the entire river would stop flowing, not just one side. Now imagine we place a water wheel in the river which slows the flow of the river. It wouldn't matter where in the circle the water wheel is placed, it will still slow the flow on the entire river.

This is an oversimplification, as the current limiting resistor cannot be placed anywhere in the circuit; it can be placed on either side of the LED to perform its function.

For a more scientific answer, we turn to Kirchoff's Voltage Law. It is because of this law that the current limiting resistor can go on either side of the LED and still have the same effect. For more info and some practice problems using KVL, visit this website.

How do I start understanding electricity?

Voltage, Current, Resistance, and Ohm's Law

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