How Many Amps Does A 100 Watt Led Bulb Draw

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 basics of electricity.

The 4 most basic physical quanities in electricity are:

Voltage (5)
Current (I)
Resistance (R)
Ability (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)
Power is measured in watts (Due west)

Electric power, or the wattage of an electrical organisation, is always equal to the voltage multiplied by the current.

A system of water pipes is ofttimes used equally an illustration to assistance people understand how these units of electricity piece of work together. In this analogy, voltage is equivalent to water pressure, current is equivalent to flow rate and resistance is equivalent to pipage size.

In electrical applied science, there is a bones equation that explains how voltage, electric current and resistance relate. This equation, written below, is known equally Ohm'south law.

Ohm's Law

V = I x R

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

One way of understanding Ohm's law is to apply it to the imaginary plumbing system we've employed as a representation of an electrical arrangement.

Let'south say nosotros have a tank of water fastened to a hose. If we increase the pressure in the tank, more h2o will come out of the hose. Thus, if we increment the voltage in an electric organization, we will also increase the current.

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

With this cursory introduction of the workings of an electrical organisation, let's jump into each of the units of electricity separately and learn most them in more than detail.

What Are Volts?

Volts are the base of operations unit used to measure Voltage. One volt is defined every bit the "difference in electric potential between ii points of a conducting wire when an electric current of i ampere dissipates one watt of ability betwixt those points." The volt is named subsequently the Italian physicist Alessandro Volta.

In our bombardment diagram to a higher place, the bombardment provides what is known as a potential departure in an electric circuit, or voltage. If nosotros go dorsum to our water analogy, the battery is like a h2o pump that propels water through a pipe. The pump increases the pressure in the pipage, causing the h2o to period.

In electrical engineering, we telephone call this electrical pressure voltage and mensurate it in volts. A voltage of three volts can be written as 3V.

As the number of volts increases, the current increases besides. But in order for the current to catamenia, the electric conductor or wire must loop back to the bombardment. If we break the circuit, with a switch for example, then no current will menses.

There are standard voltage outputs for everyday objects like batteries and household outlets. In the Us, 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 table beneath.

Common Voltages


Object	Voltage
Unmarried-jail cell, rechargeable battery	1.2V
Single-cell, non-rechargeable bombardment	1.5V–1.56V
USB	5V
Machine battery	ii.1V per cell
Electric vehicle bombardment	400V
Household outlet (Japan)	100V
Household outlet (North America)	120V
Household outlet (Europe, Asia, Africa, Australia)	230V
Rapid transit tertiary rail	600V–750V
High-voltage electric ability lines	110,000V
Lightning	100,000,000V

What Are Amps?

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

Electricity consists of the menstruation of electrons through a usher, for example, an electrical wire or cable. We mensurate the charge per unit of flow of electricity as an electric current (simply as nosotros call back of the rate of flow of water in a river as the river current). The letter used to represent current in an equation is I.

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

A current of two Amps can exist written as 2A. The bigger the current the more than electricity is flowing.

The International Organization of Units (SI) defines amps as follows:

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

Electric Electric current Sit-in (Video)

What Are Ohms?

Ohms are the base of operations unit of resistance in an electrical organization. The ohm is defined as "an electrical resistance betwixt 2 points of a conductor when a constant potential difference of ane volt, practical to these points, produces in the conductor a current of one ampere, the conductor not being the seat of whatever electromotive force." The ohm is named after the German physicist Georg Simon Ohm.

Resistance is measured in ohms, or Ω (omega), for short. So, v ohms can be 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 bombardment would get very hot and the battery would soon be flat because there would be well-nigh no resistance in the circuit. Without any resistance, a huge electrical current would menstruation until the bombardment was empty.

In one case we add together a bulb to the circuit, resistance is created. At that place is now a local "blockage" (or narrowing of the pipe, per our water pipe analogy) where the current experiences some resistance. This profoundly reduces the electric current flowing in the circuit, then the energy in the bombardment is released more slowly.

As the battery forces the electric current through the bulb, the battery'due south energy is released in the bulb in the class of light and estrus. In other words, the electric current carries stored energy from the battery to the bulb, where it is turned into light and heat energy.

The image above shows a light bulb as the main cause of electrical resistance. — The epitome above shows a light seedling as the primary crusade of electrical resistance.

What Are Watts?

A watt is the base unit of measurement of ability in electrical systems. It can too be used in mechanical systems. It measures how much free energy is released per 2nd in a organisation. In our bombardment diagram, the size of both the voltage and the electric current in the seedling determine how much free energy is released.

In the diagram above, the calorie-free bulb would go brighter every bit the power, measured in watts, increases.

Nosotros can summate the power released in the bulb, and of the electrical system as a whole, past multiplying the voltage by the current. Then, to calculate watts, the following formula is used.

How to Calculate Watts

Due west = V * I

For case, 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 adding involving voltage, current, resistance, or power, reference the formulae circle beneath. For example, we can summate the power in watts by referencing the yellowish expanse in the circle.

This formulae circle is very useful for many electrical technology tasks. Keep it handy the next fourth dimension you are dealing with an electric system.

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

Example Equations

1. What is the current in an electric 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.

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

Five = I x R

V = 10 x 200

Five = 2000V

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

3. What is the resistance in an electrical arrangement with a voltage of 230V and a current of 5A?

R = Five/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

After reading this article, you lot hopefully have a better agreement of the difference between electric electric current, voltage, resistance, and electrical ability. Remember that if you know whatsoever two of the physical values in the formulae circumvolve then you lot can calculate each of the other two unknown values.

Basic Electricity Tutorial (Video)

Electricity Quiz

For each question, choose the all-time reply. The respond key is below.

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

Reply Cardinal

0.5A
iv.5W

Interpreting Your Score

If you lot got 0 correct answers: Perhaps you need to reread this commodity?

If you got 1 correct answer: Exercise you see where you went wrong?

If you lot got 2 correct answers: Well done. You certainly know Watt is Watt!

Questions & Answers

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

Answer: R= 5/I = 115/8 = 14.iv Amps

Question: Can I run two appliances at the same time when the max amps available is 5A? One requires 3 amp, and the other requires 4.15 amp.

Answer: The answer is no. The total current drawn is seven.fifteen Amps. This would overload a 5A socket, and result in a 5A fuse bravado or a 5A circuit breaker being triggered.

Robert on May 26, 2022:

Very informative and helpful.

James Watt on April 23, 2022:

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

Dennis on Apr 09, 2022:

Very useful, insight

CR7 on March 24, 2022:

Blurry images

Rooprick on November 22, 2022:

I'one thousand trying to attach a cork to my Fork so when I eat I don't injure myself or others how do I do that

brit on November 21, 2022:

cool

Branson on September 24, 2022:

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

remlalnghaka on September 21, 2022:

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ubaid on July 31, 2022:

how much units volition be comsumed by an electronic device of three amps per hr

manivannan on July 18, 2022:

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Ghulab hameed on May 15, 2022:

sir plz tell me how we know a device how many voltage applied and which condination volition be prove?

Krystal on May 14, 2022:

Trying to get the answer to this question can anybody help me please demand if by the moring for school

ane. Question:

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

Heidy on April 01, 2022:

thanks for explaining the nuts of electricity. It make sense now

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COOPER IS Elementary on February 11, 2022:

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robert cannon on January 21, 2022:

I don't care about modest electrical quiz I what one question answered what gauge wire is needed to hook up a welder rated at 230 volts 220 amps as far as I got as it is with electricity is this loftier a amperage will impale you

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Cooper on October thirty, 2022:

So we know plugging an extension into another extension (and having load being fatigued from said setup) volition (peradventure) hitting the maximum immune Amperage/Wattage for that extension and burn information technology out...

But nosotros can take multiple devices like Fridges, Freezers, Television set'southward, Irons, etc, etc... Each on their ain "Plug Socket" but aren't the Plug Sockets essentially just 'extensions' of the house Mains? -

Presuming my reply is probably bachelor on the business firm's Principal Fuse Board?... I'1000 curious to inquire how ane would calculate the Maximum Potential Amperage & Wattage load of ane's entire house!

I know I could add up all my devices and summate 'My Specific Total Describe' simply how much further 'til I hit the 'maximum for my residence'?

The reply is probably stupidly elementary, just I'm being stupidly simple at the moment so such an answer would be warranted :D

- Cooper

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hi babe on July 03, 2022:

very good and very helpful

Brunsrm on April 02, 2022:

Tin 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 3 A.

Thanks for your help

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andrea Sherman on September 04, 2022:

I never understood how that worked. I still am sort of confused . isn't electricity measured in both particles and linear?. I took a class called physics for poets about 40 years ago. thank you✌

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cool

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hi there, i am only getting to know about electricity. and has always been confused to hell, what is Amps, Volts etc. now i understood it all.

thanks for the commodity. God Bless

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Being engineer myself I enjoyed reading the concepts.

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Very good

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

Marj

Someone on March 08, 2022:

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Thanks a lot for your wonderful detail explainatin. I hope information technology would be very helpful to all beginers. All-time wishes for your blog.

Alpo on Jan 05, 2022:

Thank you for the tutorial...it has been awhile and was looking for the bones equations. According to your article, "A" is short for amperes or amps. Subsequently, "I" is introduced without relating it to amps. For clarity, you might add that.

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Alex on May 22, 2022:

Can someone help to discover out 12 volt ??? due west required in the given satiation?

I required 220 volt chiliad west to run my application. i am planning to install solar console to have total fill my requirement. it involve solar panel ,12 volt battery, and power inverter, how many watts of 12 volt panel do i required to have 220 volt 1000w ability to run my application

Rusty on April 09, 2022:

I establish information technology interesting that elkangorito said no style 120 is safer than 230 volts. And so why in England on ALL commercial piece of work sites the max voltage used is 120? Everything is stepped downwardly 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:

Skillful explanation with examples

ajay on April sixteen, 2022:

thanks for the reply. sir please requite i more answer about transformers. I read somewhere that transformers can increment and decrease the voltage of a said line, and so in that example is information technology possible to subtract the incomming 220v principal line of my business firm to say 24v and then again increase it 220v for normal usage. will the performance exist the aforementioned and volition information technology decrease the electrical bill.

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

ajay - the maximum current would depend on the fuse or breaker in the excursion. In theory, if you short circuited the 120v you could get an infinite current but domestic supplies normally have a breaker that trips if you draw besides much current. In the UK, our domestic circuits typically permit you to draw virtually 13A from a 3 pivot plug simply information technology my be higher elsewhere, for example the U.s.a..

ajay on Apr 14, 2022:

how exercise we decide the maximum limit of ampereage that can exist fatigued out of a 120 volts line

Ak on December 28, 2022:

Thank you for the heads-up Rik. I want to implement cheap renewable free energy, could y'all outline few options? Pv or solar panels are not the options where i live. 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 go electric energy for nothing. You can catechumen mechanical energy into electrical free energy, a generator does this. But y'all still have to put the same amount of energy in. Scammers sometimes talk most perpetual move in connectedness with free free energy but it doesn't exist.

Ak on December 21, 2022:

I have a question.. Tin the magnetic energy be converted to electric enegergy somehow by properly placing them on a flywheel? Rotating the flywheel using the magnetic force. In that location are lot of things going on the web about information technology. And how come they only sell guides but not the finished product.

Ak on December 21, 2022:

Clear every bit crystal

Robert on Dec 18, 2022:

Kickoff, thank you lot does not say plenty for this. I am a wearisome learner and forrard to using this to assistance learn well-nigh electricity. I am finding out that it is not that hard, but like Bert K commented, U+P=R. Give thanks you over again and so much Mr. Ravado

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

Brett

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

Brett on November x, 2022:

Shouldn't your graphic read I = sqrt(P) / R instead of I = sqrt(P) / 5?

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

Cheers for the feedback Bert - y'all are and then right with U+P=R.

Learning is much more effective when you put what you lot have learned into practice!

bert yard on March 12, 2022:

thanks for the free lesson. y'all made it very clear and easy to understand. here is a smart formula i'd similar to pass on to beginners like myself. U+P=R or utilization plus do equals retentiveness. i wish at that place had been net and google when i was a kid. best regards teach. bk

topquark from Britain on Feb 07, 2022:

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

bernie on Oct 12, 2022:

Everyones a cridic. I understood completely and I understood that it is not on the money, and those of us who don't accept to act like know information technology all'southward realize that there are factors involved that makes the math shut, but there is room for error. Maybe thicknees of the wire being used, bombardment losing power, or whatever the reason. People chill!!! If I understood and realise this then you lot encephalon childeren should. Anal Bastards.

Kevin on October 03, 2022:

Thank you for this mate.

Helped a lot with my schoolwork. :P

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

Thanks Peter!

Peter Enmore on June 08, 2022:

Yeah, yous really can't get the adding it to an exact. Only you lot can definitely go an approximate.

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

Elk

Thanks for your comments - I withal 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' every bit manifestly cablevision and other elements in the circuit will further lower the electric current. Also the rating of the bulb or other appliance will not be precise and there will exist a margin of error.

Thank you for stopping by and commenting!

elkangorito from Thailand on February 06, 2022:

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

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

This is non true.

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

Secondly, the voltage in the U.s.a. is 120v (domestic).

120v is in no mode "safer" than 230v. A "rubber" voltage is considered to be less than 50v RMS (Ac) or 120v DC (ripple free). These voltages are known every bit "extra low voltages" & relate to "touch voltage limits".

You likewise said: "Finally, recollect that if you know the voltage of your power supply and so y'all can summate the electric current through a bulb, fuse or other electric appliance or component, based on its rating in Watts."

I think that you meant to say, "Finally, remember that if yous know the voltage of your power supply and so y'all 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 you found it helpful!

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

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

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

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