A 2,000-watt Heater Draws 8 Amps. What Is Its Rated Voltage?

Rik is an engineer who has held a range of marketing, technical support, and management roles. He is also a qualified teacher.

Welcome to your guide to the nuts of electricity.

The four most basic physical quanities in electricity are:

Voltage (V)
Electric current (I)
Resistance (R)
Power (P)

Each of these quantities are measured using different units:

Voltage is measured in volts (Five)
Current is measured in amps (A)
Resistance is measured in ohms (Ω)
Ability is measured in watts (W)

Electrical ability, or the wattage of an electric organization, is e'er equal to the voltage multiplied by the electric current.

A system of water pipes is often used as an analogy to help people sympathise how these units of electricity work together. In this illustration, voltage is equivalent to water pressure, current is equivalent to flow rate and resistance is equivalent to pipe size.

In electrical engineering, there is a bones equation that explains how voltage, current and resistance chronicle. This equation, written below, is known as Ohm'south law.

Ohm's Law

V = I x R

Ohm's law states that voltage is equal to the current flowing in a circuit times the resistance of the excursion.

One mode of agreement Ohm's law is to apply information technology to the imaginary plumbing arrangement nosotros've employed as a representation of an electric organisation.

Let's say we take a tank of h2o attached to a hose. If we increase the pressure level in the tank, more h2o volition come out of the hose. Thus, if we increase the voltage in an electrical system, nosotros will too increase the current.

If nosotros make the bore of the hose smaller, resistance will increase, causing less water to come out of the hose. Thus, if nosotros increment the resistance in an electric system, nosotros will decrease the current.

With this brief introduction of the workings of an electric system, permit'due south jump into each of the units of electricity separately and learn about them in more detail.

What Are Volts?

Volts are the base unit used to measure Voltage. 1 volt is defined equally the "departure in electrical potential between ii points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points." The volt is named after the Italian physicist Alessandro Volta.

In our battery diagram in a higher place, the battery provides what is known equally a potential difference in an electric excursion, or voltage. If we become back to our water analogy, the battery is like a water pump that propels water through a pipe. The pump increases the pressure in the piping, causing the water to catamenia.

In electrical engineering, we telephone call this electric pressure level voltage and measure out it in volts. A voltage of three volts tin be written every bit 3V.

Every bit the number of volts increases, the electric current increases also. But in order for the electric current to flow, the electrical conductor or wire must loop back to the battery. If we pause the circuit, with a switch for instance, then no current will menstruum.

There are standard voltage outputs for everyday objects like batteries and household outlets. In the U.s.a., the standard voltage output for a household outlet is 120V. In Europe, the standard voltage output for a household outlet is 230V. Other standard voltage outputs are listed in the tabular array below.

Common Voltages


Object	Voltage
Single-jail cell, rechargeable battery	i.2V
Unmarried-prison cell, non-rechargeable bombardment	1.5V–1.56V
USB	5V
Motorcar bombardment	two.1V per cell
Electric vehicle bombardment	400V
Household outlet (Nihon)	100V
Household outlet (Northward America)	120V
Household outlet (Europe, Asia, Africa, Commonwealth of australia)	230V
Rapid transit third track	600V–750V
High-voltage electrical power lines	110,000V
Lightning	100,000,000V

What Are Amps?

The ampere, oftentimes shortened to "amp" or A, is the base unit of electric current in the International Organisation of Units. It is named after the French mathematician and physicist André-Marie Ampère, who is considered the father of electrodynamics.

Electricity consists of the menses of electrons through a conductor, for case, an electric wire or cable. We measure the charge per unit of period of electricity as an electric current (merely as we think of the rate of flow of water in a river equally the river current). The letter used to represent current in an equation is I.

Electric electric current is measured in Amperes, shortened to Amps or simply the alphabetic character A.

A current of ii Amps can be written equally 2A. The bigger the current the more than electricity is flowing.

The International System of Units (SI) defines amps every bit follows:

"The ampere is that constant current which, if maintained in 2 straight parallel conductors of infinite length, of negligible circular cross-department, and placed ane metre autonomously in a vacuum, would produce between these conductors a strength equal to 2×10⁻⁷ newtons per metre of length."

Electric Electric current Demonstration (Video)

What Are Ohms?

Ohms are the base unit of resistance in an electrical organization. The ohm is divers equally "an electric resistance between 2 points of a conductor when a constant potential deviation of one volt, applied to these points, produces in the usher a current of i ampere, the conductor not beingness the seat of any electromotive force." The ohm is named subsequently the High german physicist Georg Simon Ohm.

Resistance is measured in ohms, or Ω (omega), for short. So, 5 ohms can exist written 5Ω.

In our battery diagram above, if we remove the bulb and reconnected the wire so the battery was short circuited, the wire and battery would get very hot and the battery would soon be apartment because there would be virtually no resistance in the excursion. Without any resistance, a huge electrical electric current would flow until the battery was empty.

One time we add a bulb to the circuit, resistance is created. There is now a local "blockage" (or narrowing of the pipe, per our water piping illustration) where the current experiences some resistance. This greatly reduces the current flowing in the circuit, so the energy in the battery is released more slowly.

Equally the battery forces the current through the bulb, the battery's energy is released in the seedling in the course of low-cal and estrus. In other words, the current carries stored free energy from the bombardment to the seedling, where it is turned into light and estrus energy.

The image above shows a light bulb as the main cause of electrical resistance. — The image above shows a lite bulb equally the main cause of electrical resistance.

What Are Watts?

A watt is the base unit of power in electric systems. Information technology can too exist used in mechanical systems. Information technology measures how much energy is released per 2nd in a system. In our battery diagram, the size of both the voltage and the electric current in the bulb determine how much energy is released.

In the diagram above, the light bulb would get brighter every bit the power, measured in watts, increases.

We tin calculate the power released in the seedling, and of the electrical organisation as a whole, by multiplying the voltage by the electric current. So, to calculate watts, the following formula is used.

How to Summate Watts

West = V * I

For example, a electric current of 2A flowing through a bulb with a voltage of 12V across it generates 24W of power.

How to Calculate with Watts, Amps, Volts, and Ohms

If you want to do an electrical calculation involving voltage, electric current, resistance, or power, reference the formulae circle beneath. For case, we tin summate the power in watts past referencing the yellow area in the circle.

This formulae circle is very useful for many electric engineering tasks. Proceed it handy the next time you are dealing with an electrical system.

Below are some example equations that are solved using the formulae.

Instance Equations

1. What is the electric current in an electrical circuit with a voltage of 120V and 12Ω of resistance?

I = Five/R

I = 120/12

I = 10A

The current in an electrical excursion with a voltage of 120V and 12Ω of resistance is 10A.

ii. What is the voltage across an electric circuit with a current of 10A and 200Ω of resistance?

5 = I x R

V = 10 x 200

V = 2000V

The electric current in an electrical system with 10A and 200Ω of resistance is 2000V.

iii. What is the resistance in an electric organization with a voltage of 230V and a electric current of 5A?

R = V/I

R = 230/5

R = 46Ω

The resistance in an electric system with 230V and 50A is 46Ω.

Formulae circle for solving electrical unit equations. — Formulae circumvolve for solving electrical unit equations.

In Conclusion

Afterward reading this commodity, you hopefully have a ameliorate agreement of the difference between electrical electric current, voltage, resistance, and electrical power. Recollect that if you know any two of the concrete values in the formulae circumvolve then you can calculate each of the other two unknown values.

Basic Electricity Tutorial (Video)

Electricity Quiz

For each question, choose the best answer. The reply key is below.

If I connect a 120V supply to a 60W bulb, what current would menstruum in the excursion?
- 1A
- 2A
- 0.5A
- 5A
If a 3V battery is continued to a bulb and a current of 1.5A flows through it then what is the rating of the bulb?
- 3W
- 2W
- four.5W
- 0.5W

Answer Key

0.5A
four.5W

Interpreting Your Score

If you got 0 correct answers: Perchance yous need to reread this article?

If y'all got 1 correct answer: Practice you see where you went wrong?

If you got ii correct answers: Well done. You certainly know Watt is Watt!

Questions & Answers

Question: What is the resistance of the heating chemical element of an electric fe if the ampere describe is 8 amperes when 115 volts are applied?

Respond: R= Five/I = 115/8 = fourteen.4 Amps

Question: Tin can I run two appliances at the aforementioned time when the max amps available is 5A? Ane requires iii amp, and the other requires 4.15 amp.

Answer: The reply is no. The full current drawn is 7.fifteen Amps. This would overload a 5A socket, and outcome in a 5A fuse blowing or a 5A circuit billow being triggered.

Robert on May 26, 2022:

Very informative and helpful.

James Watt on April 23, 2022:

"and Watts are named after Scottish inventor and mathematician James Watt"

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CR7 on March 24, 2022:

Blurry images

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brit on November 21, 2022:

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Branson on September 24, 2022:

I am trying to design a bombardment power led light strip. My question is if my led controller is 12v, what amperage 12v bombardment supply tin I use? 2A? 4A? 6A?

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ubaid on July 31, 2022:

how much units volition be comsumed by an electronic device of iii amps per hour

manivannan on July xviii, 2022:

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Ghulab hameed on May 15, 2022:

sir plz tell me how nosotros know a device how many voltage applied and which condination will exist evidence?

Krystal on May 14, 2022:

Trying to get the reply to this question can anybody assistance me please demand if by the moring for schoolhouse

1. Question:

I=.5amps,R=50phms,P=

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So we know plugging an extension into another extension (and having load being drawn from said setup) will (possibly) striking the maximum allowed Amperage/Wattage for that extension and burn it out...

Only we can take multiple devices like Fridges, Freezers, Television set's, Irons, etc, etc... Each on their own "Plug Socket" only aren't the Plug Sockets substantially only 'extensions' of the business firm Mains? -

Presuming my answer is probably available on the house'due south Primary Fuse Board?... I'chiliad curious to enquire how i would summate the Maximum Potential Amperage & Wattage load of one's entire firm!

I know I could add upwardly all my devices and summate 'My Specific Total Draw' but how much farther 'til I hit the 'maximum for my residence'?

The answer is probably stupidly simple, but I'chiliad beingness stupidly simple at the moment and then such an answer would be warranted :D

- Cooper

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Brunsrm on April 02, 2022:

Can I run two appliances at the same time when the max electric provided is 5 amps? One requires 4.12 A and the other requires three A.

Cheers for your assistance

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hullo there, i am simply getting to know almost electricity. and has ever been confused to hell, what is Amps, Volts etc. now i understood it all.

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Being engineer myself I enjoyed reading the concepts.

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Please advise this old lady if I can use Gu10 replacement bulbs with 110/220 in the britain, as I bought them in fault, thanking you in anticipation,

Marj

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Thank you a lot for your wonderful detail explainatin. I hope it would be very helpful to all beginers. All-time wishes for your blog.

Alpo on Jan 05, 2022:

Thanks for the tutorial...it has been awhile and was looking for the basic equations. Co-ordinate to your commodity, "A" is curt for amperes or amps. Later, "I" is introduced without relating it to amps. For clarity, y'all might add that.

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Alex on May 22, 2022:

Can someone assist to notice out 12 volt ??? w required in the given satiation?

I required 220 volt thousand west to run my application. i am planning to install solar panel to take total fill my requirement. information technology involve solar console ,12 volt bombardment, and power inverter, how many watts of 12 volt panel do i required to have 220 volt 1000w power to run my application

Rusty on April 09, 2022:

I found it interesting that elkangorito said no way 120 is safer than 230 volts. Then why in England on ALL commercial work sites the max voltage used is 120? Everything is stepped down from 230 to 120.

Thanks

Kiran Chandran on October 04, 2022:

I had cleared many doubts by using this........

amped on July 17, 2022:

Very useful explanation.

saratchandra on May 25, 2022:

Good explanation with examples

ajay on April 16, 2022:

thanks for the answer. sir delight requite i more answer about transformers. I read somewhere that transformers tin increment and decrease the voltage of a said line, so in that case is it possible to subtract the incomming 220v main line of my house to say 24v and and so again increase it 220v for normal usage. will the performance be the same and will it decrease the electric bill.

Rik Ravado (author) from England on April 14, 2022:

ajay - the maximum current would depend on the fuse or breaker in the circuit. In theory, if you brusque circuited the 120v you could get an infinite electric current merely domestic supplies normally have a breaker that trips if you draw too much current. In the UK, our domestic circuits typically allow you to describe most 13A from a iii pin plug but information technology my be college elsewhere, for example the US.

ajay on Apr 14, 2022:

how practise we determine the maximum limit of ampereage that can be drawn out of a 120 volts line

Ak on December 28, 2022:

Thanks for the heads-up Rik. I want to implement cheap renewable energy, could you outline few options? Pv or solar panels are not the options where i alive. I heard a lot about fuel cells, are they expensive?

Rik Ravado (author) from England on December 22, 2022:

Ak - These products are all scams. You don't get electrical energy for goose egg. You can convert mechanical energy into electrical free energy, a generator does this. Just y'all still have to put the same amount of energy in. Scammers sometimes talk about perpetual motion in connexion with complimentary energy merely information technology doesn't exist.

Ak on December 21, 2022:

I have a question.. Can the magnetic energy be converted to electric enegergy somehow by properly placing them on a flywheel? Rotating the flywheel using the magnetic forcefulness. There are lot of things going on the web nigh it. And how come they only sell guides but not the finished product.

Ak on December 21, 2022:

Clear as crystal

Robert on Dec 18, 2022:

First, thank y'all does not say enough for this. I am a slow learner and frontwards to using this to help acquire nigh electricity. I am finding out that information technology is not that hard, but like Bert Thousand commented, U+P=R. Thank you again so much Mr. Ravado

Rik Ravado (author) from England on November 11, 2022:

Brett

Well spotted - I concur. (Inverse the graphic) Thanks!

Brett on November 10, 2022:

Shouldn't your graphic read I = sqrt(P) / R instead of I = sqrt(P) / Five?

Rik Ravado (author) from England on March 12, 2022:

Thanks for the feedback Bert - you lot are so right with U+P=R.

Learning is much more constructive when you put what y'all have learned into practice!

bert 1000 on March 12, 2022:

thanks for the gratis lesson. y'all made it very clear and easy to understand. here is a smart formula i'd like to laissez passer on to beginners like myself. U+P=R or utilization plus practice equals retention. i wish there had been cyberspace and google when i was a kid. best regards teach. bk

topquark from UK on February 07, 2022:

Useful and well-presented commodity! A lot of people seem to get confused about Watts and Amps and Volts - an explanation like this has been long overdue.

bernie on Oct 12, 2022:

Everyones a cridic. I understood completely and I understood that information technology is non on the money, and those of us who don't have to deed like know it all'due south realize that there are factors involved that makes the math close, but in that location is room for error. Maybe thicknees of the wire being used, battery losing power, or any the reason. People chill!!! If I understood and realise this so you brain childeren should. Anal Bastards.

Kevin on October 03, 2022:

Cheers for this mate.

Helped a lot with my schoolwork. :P

Rik Ravado (author) from England on June 09, 2022:

Thanks Peter!

Peter Enmore on June 08, 2022:

Yes, you actually can't get the adding it to an exact. Simply yous tin definitely get an approximate.

Rik Ravado (author) from England on Feb 06, 2022:

Elk

Thanks for your comments - I even so maintain 120v is safer than 230v. In other words the lower the voltage, the less current potentially flows through the victim.

I agree with your 'approximately' as manifestly cable and other elements in the circuit will further lower the current. Also the rating of the bulb or other apparatus volition not be precise and there will be a margin of mistake.

Thanks for stopping past and commenting!

elkangorito from Thailand on February 06, 2022:

Even though your blog is an excellent "guide to the nuts of electricity", there are a couple of things that need to exist considered:

You said, "In the USA, the domestic supply is typically 110V, much safer than the UK."

This is not true.

Firstly, the voltage in the U.k. is officially 230v (single phase, domestic).

Secondly, the voltage in the The states is 120v (domestic).

120v is in no way "safer" than 230v. A "safety" voltage is considered to be less than 50v RMS (Air-conditioning) or 120v DC (ripple free). These voltages are known every bit "actress low voltages" & relate to "touch voltage limits".

You besides said: "Finally, recall that if you know the voltage of your ability supply and then you lot can calculate the current through a bulb, fuse or other electrical appliance or component, based on its rating in Watts."

I think that you meant to say, "Finally, call up that if yous know the voltage of your power supply then you tin can APPROXIMATELY calculate the current through a bulb, fuse or other electrical appliance or component, based on its rating in Watts."

Rik Ravado (author) from England on November 04, 2009:

LiamBean - glad y'all found it helpful!

LiamBean from Los Angeles, Calilfornia on Oct 23, 2009:

Lovely. Wonderful explanation of Watts, Amps, and Current.

Source: https://owlcation.com/stem/Watt-are-Amps-and-Volts

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