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Electricity is all around us, powering technology like our cell phones, computers, lights, welders and air conditioners. It's hard to escape this in our modern world. Even when you try to escape electricity, it continues to work throughout nature, from lightning in a thunderstorm to the synapses inside our bodies. but what exactlyeselectricity? This is a very complicated question, and as you dig deeper and ask more questions, there really isn't a definitive answer, just abstract representations of how electricity interacts with our environment.
Electricity is a natural phenomenon that occurs throughout nature and takes many different forms. In this tutorial we're going to focus on current electricity: what powers our electronic devices. Our goal is to understand how electricity flows from a power source through wires, lighting LEDs, turning motors, and powering our communication devices.
Electricity is briefly defined as theelectric charge flow,but there is much behind that simple statement. Where do the charges come from? How do we move them? Where do they move? How does an electrical charge cause mechanical motion or make things light up? Many questions! To begin to explain what electricity is, we must look far beyond matter and molecules to the atoms that make up everything we interact with in life.
This tutorial is based on a basic understanding of physics,force,Energy,atoms, and [fields](http://en.wikipedia.org/wiki/Field_(physics)) in particular. We'll skip the basics of each of these physics concepts, but it might be helpful to consult other sources as well.
To understand the basics of electricity, we must start by focusing on atoms, one of the building blocks of life and matter. Atoms exist in over a hundred different forms as chemical elements such as hydrogen, carbon, oxygen, and copper. Atoms of many types can combine to form molecules, which form the matter we can physically see and touch.
the atoms aretiny, extending to a maximum of about 300 picometers in length (that's 3x10-10or 0.0000000003 meters). A copper penny (if it were really made of 100% copper) would be 3.2 x 1022atoms (32,000,000,000,000,000,000,000 atoms) of copper inside.
Even the atom is not small enough to explain how electricity works. We need to dive in one more level and look at the basic building blocks of atoms: protons, neutrons and electrons.
building blocks of atoms
An atom is built from a combination of three different particles: electrons, protons and neutrons. Each atom has a central nucleus, where protons and neutrons are densely packed. Around the nucleus is a group of orbiting electrons.
A very simple atomic model. Not to scale, but useful for understanding how an atom is built. A central nucleus of protons and neutrons is surrounded by orbiting electrons.
Every atom must have at least one proton in it. The number of protons in an atom is important because it defines which chemical element the atom represents. For example, an atom with a single proton is hydrogen, an atom with 29 protons is copper, and an atom with 94 protons is plutonium. This proton count is called an atom.atomic number.
The proton's companion to the nucleus, the neutrons, serve an important purpose; they keep the protons in the nucleus and determine the isotope of an atom. They are not critical to our understanding of electricity, so we won't be concerned with them in this tutorial.
Electrons are fundamental to how electricity works (see a common theme in their names?) In its most stable, balanced state, an atom will have the same number of electrons and protons. How notbohr atomic modelbelow, a nucleus with 29 protons (making it a copper atom) is surrounded by an equal number of electrons.
As our understanding of atoms has evolved, so has our method of modeling them. The Bohr model is a very useful atomic model when exploring electricity.
The electrons in the atom are not all forever bound to the atom. The electrons in the outer orbit of the atom are called valence electrons. With enough external force, a valence electron can break free of the atom's orbit and break free.free electronsit allows us to move charge, which is what electricity is all about. Speaking of charges...
As we mentioned at the beginning of this tutorial, electricity is defined as the flow of electrical charge.To loadIt is a property of matter, just like mass, volume or density. It's measurable. Just as you can quantify how much mass something has, you can measure how much charge it has. The key concept with cargo is that it can come in two types:positive (+) or negative (-).
To move the load, we needload carriers, and this is where our knowledge of atomic particles, specifically electrons and protons, comes in handy. Electrons are always negatively charged, while protons are always positively charged. Neutrons (true to their name) are neutral, they have no charge. Both electrons and protons carry the sameamountfor free, just a different kind.
A model lithium atom (3 protons) with labeled charges.
The charge of electrons and protons is important because it gives us the means to exert a force on them. Electrostatic force!
Electrostatic force (also calledLei de Coulomb) is a force operating between the charges. He states that charges of the same type repel each other, while charges of opposite types attract.Opposites attract and likes repel.
HimamountThe force acting on two charges depends on the distance between them. The closer two charges are, the greater the force becomes (either pushing or pushing away).
Thanks to electrostatic force, electrons will push other electrons and be attracted by protons. This force is part of the "glue" that holds atoms together, but it is also the tool we need to make electrons (and charges) flow!
Make the charges flow
Now we have all the tools to make the charges flow.electronsinto atoms can act as ourload bearer, because each electron carries a negative charge. If we can release an electron from an atom and force it to move, we can create electricity.
Consider the atomic model of a copper atom, one of the preferred elementary sources for charge flow. In its balanced state, copper has 29 protons in its nucleus and an equal number of electrons orbiting around it. Electrons orbit at different distances from the nucleus of the atom. Electrons closer to the nucleus feel a much stronger pull towards the center than those in distant orbits. The outermost electrons of an atom are calledvalence electrons, these require the least amount of force to break free from an atom.
This is a diagram of a copper atom: 29 protons in the nucleus, surrounded by circling bands of electrons. The electrons closest to the nucleus are difficult to remove, while the valence electron (outer ring) requires relatively little energy to be ejected from the atom.
Using enough electrostatic force on the valence electron, pushing it with another negative charge, or pulling it with a positive charge, we can force the electron out of orbit around the atom, creating a free electron.
Now consider a copper wire: matter filled with countless copper atoms. like oursfree electronit is floating in a space between atoms, it is pulled and pushed by the charges that surround it in that space. In this chaos, the free electron finally finds a new atom to bond with; in doing so, the negative charge of that electron drives another valence electron out of the atom. Now, a new electron wanders through free space looking to do the same. This chain effect can continue repeatedly to create a flow of electrons calledelectric current.
A very simplified model of charges flowing through atoms to generate current.
Some elementary types of atoms are better than others at giving up their electrons. To get the best flow of electrons possible, we want to use atoms that don't retain their valence electrons too much. The conductivity of an element measures how tightly an electron is bound to an atom.
Elements with high conductivity, which have highly mobile electrons, are calleddrivers. These are the kinds of materials we want to use to make wires and other components that help electrons flow. Metals like copper, silver, and gold are generally our top choices for good conductors.
Elements with low conductivity are calledinsulators. Insulators serve a very important purpose: they prevent the flow of electrons. Popular insulators include glass, rubber, plastic and air.
Static Electricity or Current
Before we go any further, let's discuss the two forms that electricity can take: static or current. When working with electronics, current electricity will be much more common, but it's also important to understand static electricity.
Static electricity exists when opposite charges accumulate on objects separated by an insulator. Static electricity (as in "resting") exists until the two sets of opposite charges can find a way between each other to balance the system.
When the charges find a way to equalize, astatic dischargeoccurs. The attraction of the charges becomes so great that they can flow through even the best insulators (air, glass, plastic, rubber, etc.). Static discharges can be harmful depending on the medium through which the charges travel and the surfaces to which they are transferred. The equalization of charges across an air gap can cause a visible collision when moving electrons collide with electrons in the air, which become excited and release energy in the form of light.
incendiariesare used to create a controlled static discharge. Opposite charges build up on each of the conductors until their attraction is so great that the charges can flow through the air.
One of the most dramatic examples of static discharge islighting. When a cloud system gathers enough charge relative to another cloud group or the Earth's ground, the charges will try to equalize. As the cloud discharges, large amounts of positive (or sometimes negative) charges travel through the air from the ground into the cloud, causing the visible effect we are all familiar with.
Static electricity also familiarly exists when we rub balloons on our heads to make our hair stand on end, or whenshuffle on the floorin fuzzy slippers and surprising the family cat (by accident, of course). In each case, the friction of friction between different types of materials transfers electrons. The object that loses electrons becomes positively charged, while the object that gains electrons becomes negatively charged. The two objects are attracted to each other until they find a way to combine.
When working with electronics, we usually don't have to deal with static electricity. When we do this, we are usually trying to protect our sensitive electronic components from being subjected to static discharge. Preventive measures against static electricity include wearing ESD (Electrostatic Discharge) wrist straps or adding special components in circuits to protect against very high surge loads.
Current electricity is the form of electricity that makes all of our electronic devices possible. This form of electricity exists when charges are capable ofsteady flow. Unlike static electricity where charges accumulate and remain at rest, current electricity is dynamic, charges are always in motion. We'll focus on this form of electricity for the rest of the tutorial.
To flow, electric current requires athe circuit: an endless closed loop of conductive material. A circuit can be as simple as a conducting wire connected end to end, but useful circuits often contain a combination of wires and other components that control the flow of electricity. The only rule when it comes to making circuits is thatthere can be no insulation gapson them.
If you have a wire full of copper atoms and you want to induce a flow of electrons through it,allthe free electrons need somewhere to flow in the same general direction. Copper is a great conductor, perfect for making charges flow. If a copper wire circuit breaks, charges cannot flow through the air, which will also prevent charges towards the center from getting anywhere.
On the other hand, if the wire were connected end to end, all the electrons would have a neighboring atom and they could all flow in the same general direction.
now we understandWhatelectrons can flow, but how do we get them to flow in the first place? So once electrons are flowing, how do they produce the energy needed to power light bulbs or turn motors? For that, we need to understand electric fields.
We have an idea of how electrons flow through matter to create electricity. That's all there is to electricity. Well, almost everyone. Now we need a source to induce the flow of electrons. Often this source of electron flow will come from an electric field.
What is a field?
ANcampois a tool we use to model physical interactions thatinvolves no observable contact. The fields are not seen because they have no physical appearance, but the effect they have is very real.
We are all subconsciously familiar with a certain field:earth's gravitational field, the effect of a massive body attracting other bodies. The Earth's gravitational field can be modeled with a set of vectors that all point towards the center of the planet; no matter where you are on the surface, you will feel the force pulling you towards it.
The strength or intensity of the fields is not uniform at all points in the field. The farther you are from the field's source, the less effect the field has. The magnitude of Earth's gravitational field decreases as you move away from the center of the planet.
When exploring electric fields in particular, remember how the Earth's gravitational field works, both fields share many similarities. Gravitational fields exert a force on objects of mass, and electric fields exert a force on objects of charge.
Electric fields (e-fields) are an important tool for understanding how electricity starts and continues to flow. electric fieldsdescribe the pulling or pushing force on a space between charges. Compared to Earth's gravitational field, electric fields have a big difference: while Earth's field usually only attracts other mass objects (since everything isas soon assignificantly less massive), electric fields push charges away as often as they attract them.
The direction of electric fields is always defined as thedirection in which a positive test charge would moveif it was played in the field. The test charge must be infinitely small, to prevent your charge from influencing the field.
We can start by constructing electric fields for isolated positive and negative charges. If you drop a positive test charge near a negative charge, the test charge will be attracted to thenegativeto charge. So for a single negative charge, we draw our electric field arrowspointing atin all directions. That same burden of proof fell close to anotherpositivecharge would result in an outward repulsion, which means we drawarrows coming outof the positive charge.
The electric fields of individual charges. A negative charge has an internal electric field because it attracts positive charges. The positive charge has an external electric field, pushing like charges away.
Groups of electric charges can combine to form more complete electric fields.
The uniform electronic field above points away from the positive charges, towards the negative ones. Imagine a small positive test charge falling into the electronic field; You must follow the direction of the arrows. As we have seen, electricity generally involves the flow of electrons (negative charges) flowingcontraelectric fields.
Electric fields provide us with the buoyant force we need to induce current to flow. An electric field in a circuit is like an electron pump: a large source of negative charges that can trigger electrons, which will flow through the circuit into the mass of positive charges.
electric potential energy)
When we harness electricity to power our circuits, appliances, and devices, we are actually transforming energy. Electronic circuits must be able to store energy and transfer it to other forms such as heat, light or motion. The energy stored in a circuit is called electrical potential energy.
Energy? Potential energy?
To understand potential energy, we need to understand energy in general. Energy is defined as the ability of an object to doit workson another object, which means moving that object a certain distance. the energy entersmany ways, some we can see (like mechanical) and some we can't (like chemical or electrical). Regardless of the form it is in, the energy exists in one of the twoStates: kinetic or potential.
an object haskinetic energywhen you're on the go. The amount of kinetic energy of an object depends on its mass and speed.Potential energy, on the other hand, is astored energywhen an object is at rest. Describe how much work the object could do if it were set in motion. It is an energy that we can usually control. When an object is set in motion, its potential energy is transformed into kinetic energy.
Let's use gravity again as an example. A bowling ball standing motionless on top ofcaliph's towerhas a lot of potential (stored) energy. After falling, the ball, attracted by the gravitational field, accelerates towards the ground. As the ball accelerates, potential energy is converted into kinetic energy (the energy of motion). Eventually, all the energy in the ball is converted from potential to kinetic and then to whatever it hits. When the ball is on the ground, it has very low potential energy.
electric potential energy
Just as mass in a gravitational field has gravitational potential energy, charges in an electric field have aelectric potential energy. The electric potential energy of a charge describes the amount of stored energy it has, when set in motion by an electrostatic force, this energy can be converted into kinetic energy and work can be done by the charge.
Like a bowling ball on top of a tower, a positive charge next to another positive charge has a high potential energy; if left free to move, the charge would be repelled by like charge. A positive test charge placed near a negative charge would have a low potential energy, analogous to a bowling ball on the ground.
To instill anything with potential energy, we have to doit worksmoving it at a distance. In the case of the bowling ball, the task is to lift it 163 stories against the gravity field. Likewise, work must be done to push a positive charge against the arrows of an electric field (either towards another positive charge or away from a negative charge). The further up the field the charge is, the more work you have to do. Likewise, if you try to remove a negative chargeforaa positive charge - against an electric field - you have to do work.
For any charge located in an electric field, its electric potential energy depends on the type (positive or negative), the amount of charge, and its position in the field. Electric potential energy is measured in units of joules (j).
Electric potential is based on electric potential.Energyto help define how muchenergy is stored in electric fields. It is another concept that helps us to model the behavior of electric fields. The electric potential isnotthe same as electric potential energy!
At any point in an electric field, the electric potential is theamount of electric potential energy divided by the amount of chargein this point. It removes the amount of charge from the equation and gives us an idea of how much potential energy specific areas of the electric field can provide. Electric potential comes in units of joules per coulomb (DIRECT CURRENT), which we define asvolt(V).
In any electric field there are two points of electric potential that are of great interest to us. There is a point of high potential, where a positive charge would have the highest possible energy, and a point of low potential, where a charge would have the lowest possible energy.
One of the most common terms we discuss when evaluating electricity isVoltage. A voltage is the potential difference between two points in an electric field. Voltage gives us an idea of how strong an electric field is.
With potential and potential energy under our control, we have all the necessary ingredients to generate current electricity. Let's do it!
Electricity in Action!
After studying particle physics, field theory and potential energy, we now know enough to make electricity flow. Let's make a circuit!
First let's review the ingredients we need to make electricity:
- The definition of electricity isload flow. Normally, our charges will be carried by free-flowing electrons.
- negatively chargedelectronsthey bond loosely with atoms of conductive materials. With a little push we can release electrons from atoms and make them flow in a generally uniform direction.
- a closedthe circuitconductive material provides a path for electrons to flow continuously.
- Loads are carried by aelectric field. We need a source of electric potential (voltage), which pushes electrons from a point of low potential energy to a higher potential energy.
a short circuit
Batteries are common energy sources that convert chemical energy into electrical energy. They have two terminals, which connect to the rest of the circuit. On one terminal there is an excess of negative charges, while all the positive charges merge on the other. This is an electrical potential difference waiting to act!
If we connect our wire full of conductive copper atoms to the battery, this electric field will influence the negatively charged free electrons in the copper atoms. Simultaneously pushed by the negative terminal and attracted by the positive terminal, the copper's electrons will move from atom to atom creating the flow of charge we know as electricity.
After one second of current flow, the electrons movedmuchlittle - fractions of an inch. However, the energy produced by the current flow isgigante, especially since there is nothing in this circuit that slows down the flow or consumes power. Connecting a bare conductor directly across a power source is alittle idea. Energy moves very quickly through the system and is transformed into heat in the wire, which can quickly become a molten wire or a fire.
light a lamp
Instead of wasting all that energy, not to mention destroying the battery and wire, let's build a circuit that does something useful! Generally, an electrical circuit transfers electrical energy into some other form: light, heat, motion, etc. If we connect a light bulb to the battery with wires in the middle, we have a simple and functional circuit.
Scheme: a battery (on the left) connected to a lamp (on the right); the circuit is complete when the switch is closed (above). With the circuit closed, electrons can flow, pushed from the negative terminal of the battery through the bulb to the positive terminal.
While the electrons move at a snail's pace, the electric field affects the entire circuit almost instantly (we're talking the speed of light). The electrons in the entire circuit, whether at the lowest potential, at the highest potential, or near the light bulb, are influenced by the electric field. When the switch is closed and the electrons are subjected to the electric field, all the electrons in the circuit begin to flow seemingly at the same time. The charges closest to the bulb will take a step in the circuit and begin to transform electrical energy into light (or heat).
Resources and beyond
In this tutorial, we've only uncovered a small part of the tip of the proverbial iceberg. There are still many concepts to be discovered. From here we recommend that you go directly to ourVoltage, current, resistance and Ohm's lawtutorial. Now that you know all about electric fields (voltage) and flowing electrons (current), you are well on your way to understanding the law that governs their interaction.
Interested in learning more fundamental topics?
see ourengineering fundamentalspage for a complete list of fundamental topics related to electrical engineering.
Take me there!
For more information and visualizations that explain electricity, visitthis site.
Here are some other beginner-level concept tutorials we recommend reading:
- What is a circuit?
- series and parallel circuits
Or maybe you would like to learn something practical? If so, check out some of these entry-level skill tutorials:
- How to use a multimeter
- work with wire
- sew with thread
What is electricity * Your answer? ›
Electricity is the flow of electrical power or charge. It is a secondary energy source which means that we get it from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources, which are called primary sources.What have you learned about electricity? ›
Electricity is electrons in motion. Every atom has three basic parts: electrons, protons and neutrons. An electron carries a tiny negative charge. Electricity occurs in nature in the form of lightning, electric eels and the small shock you sometimes feel when you touch a doorknob, particularly in the winter.What is electricity answer for kids? ›
Electricity is a form of energy that can give things the ability to move and work. Everything in the world around us is made of particles called protons, neutrons and electrons. These three tiny particles are found in everything around us. When the electrons move, they create electricity.Why do we need electricity very short answer? ›
Electricity is a form of energy and we need it for just about everything! Almost all of our modern conveniences are electrically powered. Electricity is what lights up our classrooms, heats our homes and lets us listen to our favourite music.What is electricity in simple words? ›
Electricity is the flow of electrical power or charge. Electricity is both a basic part of nature and one of the most widely used forms of energy.What is the simplest definition of electricity? ›
The definition of electricity is the flow of charge. Usually our charges will be carried by free-flowing electrons. Negatively-charged electrons are loosely held to atoms of conductive materials.What are 5 things about electricity? ›
- Ever wondered how fast does electricity travel? ...
- Lightning is caused by the discharge of electricity in the atmosphere.
- Electricity was first discovered in 600BC.
- Electric cars actually date back as far as 1832.
- Electric eels can produce up to a 600-volt shock.
- 54% of all electricity is wasted.
It is extremely important that you impart the same knowledge to your kids so that they learn how to be careful around electricity as it is all around them since they work on computers, encounter cords, appliances, power lines and outlets, etc.What is electricity for 5th grade? ›
Electricity is a form of energy that can gives things the ability to move and work. It is the flow of tiny particles called electrons. Thus, electricity is the form of energy that we get when electrons flow from one place to another.What is the main purpose of electricity? ›
Electricity is an essential part of modern life and important to the U.S. economy. People use electricity for lighting, heating, cooling, and refrigeration and for operating appliances, computers, electronics, machinery, and public transportation systems.
What are the 4 types of electricity? ›
These days it even powers many of our cars. You could travel to the most uninhabited areas of the earth and still find it in the clouds above you during a storm. Electricity takes different forms: coal, water, solar, wind, nuclear, hydro and solar.Why is electricity the most important energy? ›
Electrical energy is one of the most commonly used forms of energy in the world. It can be easily converted into any other energy form and can be safely and efficiently transported over long distances. As a result, it is used in our daily lives more than any other energy source.What is electricity for kids easy? ›
Electricity is an energy. This energy can be used to power electrical items such as toasters, kettles, cookers, televisions and computer tablets. Electrical energy is caused by electrons (the particles in atoms) moving about to make a current.What makes electricity? ›
According to the U.S. Energy Information Administration, most of the nation's electricity was generated by natural gas, nuclear energy, and coal in 2020. Electricity is also produced from renewable sources such as wind, hydropower, solar power, biomass, wind, and geothermal.What are the main 10 uses of electricity? ›
- Transport and Communication.
- Electricity travels at the speed of light -- more than 186,000 miles per second!
- A spark of static electricity can measure up to 3,000 volts.
- Lightning is a discharge of electricity in the atmosphere.
There are two main types of electricity, Static Electricity, generated by rubbing two or more objects causing to build up friction, Current Electricity, generated by the flow of electrical charge through a conductor across an electrical field.How does electricity make your life easier? ›
It is used for lighting rooms, working fans and domestic appliances like using electric stoves, A/C and more. All these provide comfort to people. In factories, large machines are worked with the help of electricity. Essential items like food, cloth, paper and many other things are the product of electricity.What are the two rules of electricity? ›
Rule 1 – Electricity will always want to flow from a higher voltage to a lower voltage. Rule 2 – Electricity always has work that needs to be done.What is the most important rule of electricity? ›
1. Always Disconnect. The first rule of electrical safety is to always disconnect whatever you're working on. This might mean unplugging an appliance that requires repairs or turning off a circuit breaker.
What are the 4 most important units of electricity? ›
Volts, amps, ohms, and watts are therefore the four fundamental units of electricity.What is electricity facts for kids? ›
Electricity is a type of energy that comes from the flow of electrical power, also known as a charge. Electricity is used to power our homes, lights and electronics. We get electricity from sources like coal, energy, natural gas and oil.Is electricity a easy chapter? ›
Remember that the chapter on Electricity is one of the most interesting and easiest chapters in your syllabus that is very scoring.How do you explain electricity to a 6 year old? ›
To help a child understand the properties of static electricity, rub a balloon on your hair or a wool blanket or sweater, and watch how it sticks to the wall for a few moments. Explain that this is an example of negatively and positively charged atoms reacting to each other.What is electricity for grade 1? ›
Electricity is a type of energy that gives items the power to work. It flows along wires and can even flow through the air. We all use electricity every day, whether it is turning on the lights in our house, playing our favourite video game, or blow drying our hair.How electricity flows? ›
Electric Current is the flow of electrons through a wire or solution. In a solid the electrons are passed from one positively charged metallic atom to next but in solution the electron is carried by the ions present in the solution. A solution capable of carrying charge is called an electrolyte.How electricity has changed our life? ›
Electrical Appliances Are Here to Stay
Another major change in people's routine was the invention of electrical appliances, now an essential part of the operation of every home. First came the iron, and it was followed by refrigerators, washing machines, and others.
- Avoid frayed or damaged cords. If electricity is flowing through a wire and the plastic or rubber covering of the wire is damaged, touching it might electrocute you. ...
- Don't mix electricity and water. Water conducts electricity really well. ...
- Be extra careful around high-voltage devices.
Living without electricity isn't as hard as you'd think
Before Benjamin Franklin figured out electricity, we all lived without it. Nearly 250 thousand Amish people still live without electricity today, not to mention the thousands of people in developing countries.
Lightning, batteries and even electric eels are examples of electrical energy in action!
What are the two types of circuit? ›
There are two types of circuits found in homes and other common devices; namely series circuits and parallel circuits.What will happen without electricity? ›
People will have to stay in the dark in the night. Major events will not be able to bebroadcast around the world. The police services would find trouble connecting to the people. The most one would suffer would be due to the lack of medical services.What would life without electricity? ›
There would be no power to use your fridge or freezer, telephone lines would be down and phone signal lost. Your mobile phones will be useless as the battery dwindles, with no back up charging option. Your gas central heating won't work and your water supply would soon stop pumping clean water.How many types of electricity are there? ›
There are two kinds of current electricity: direct current (DC) and alternating current (AC).What is electricity science quizlet? ›
electricity. a form of energy created by charged or moving electrons or protons. attract. to pull.What is electricity science Grade 8? ›
Electricity is a natural phenomenon that can be both invisible AND visible, both matter and energy, a type of wave made of protons or a force that cannot be seen. It can move at the speed of light... yet it vibrates in a cord without flowing at all.