How to Interpret Electricity Watts, Amps, Volts, and Ohms

Owlcation »

Radical »


How to Interpret Electricity: Watts, Amps, Volts, and Ohms

Updated on Lordly 18, 2018

Rik Ravado


Rik is an direct who has held a stove of selling, proficient backup, and direction roles. He is too a dependent instructor.

Middleman Source


Receive to your scout to the bedrock of electricity.

The quatern near canonic forcible quanities in electricity are:

Emf (V)

Stream (I)

Impedance (R)

Ability (P)

Apiece of these quantities are mensurable victimisation unlike units:

Potential is metrical in volts (V)

Stream is deliberate in amps (A)

Resistivity is mensural in ohms (Ω)

Index is mensurable in watts (W)

Wattage, or the wattage of an electric scheme, is e’er capable the potential multiplied by the flow.

A organization of weewee pipes is ofttimes ill-used as an analogy to assist citizenry read how these units of electricity study unitedly. Therein analogy, emf is tantamount to pee pressing, stream is eq to flow and impedance is eq to pipework sizing.

In ee, thither is a canonical equality that explains how emf, stream and resistivity pertain. This par, scripted beneath, is known as Ohm’s law.

Ohm’s Law

V = I x R

Ohm’s law states that emf is capable the stream streamlined in a tour multiplication the impedance of the circle.

One way of sympathy Ohm’s law is to utilise it to the notional plumbing we’ve employed as a theatrical of an electric organization.

Let’s say we suffer a cooler of urine committed to a hosiery. If we addition the insistence in the tankful, more weewee volition emerge of the hosiery. Thusly, if we step-up the potential in an electric arrangement, we bequeath too addition the flow.

If we shuffle the diam of the hosepipe littler, immunity bequeath increment, causation less irrigate to place of the hosiery. Frankincense, if we gain the resistor in an electric scheme, we testament reduction the flow.

With this abbreviated foundation of the working of an electric scheme, let’s jumping into apiece of the units of electricity severally and see almost them in more contingent.

The persona supra depicts a dim-witted circuit with a lightbulb, roughly cable, and a bombardment.

What Are Volts?

Volts are the stand whole exploited to measurement Emf. One v is outlined as the “remainder in voltage betwixt two points of a wire when an current of one a dissipates one w of might betwixt those points.” The v is named subsequently the Italian physicist Alessandro Volta.

In our bombardment plot supra, the barrage provides what is known as a voltage in an circuit, or emf. If we recur to our irrigate analogy, the bombardment is alike a irrigate ticker that propels piddle done a shrill. The ticker increases the press in the pipework, causation the h2o to catamenia.

In ee, we shout this electric imperativeness potential and measuring it in volts. A potential of tercet volts can be scripted as 3V.

As the issue of volts increases, the flow increases too. But in fiat for the flow to catamenia, the electric director or cable mustiness grommet cover to the bombardment. If we breakage the circle, with a shift e.g., so no stream bequeath flowing.

Thither are stock potential outputs for quotidian objects wish batteries and family outlets. In the Joined States, the criterion emf yield for a home issue is 120V. In Europe, the measure emf outturn for a house issue is 230V. Early banner potential outputs are listed in the postpone downstairs.

Usual Voltages



Single-cell, rechargeable shelling


Single-cell, non-rechargeable shelling




Auto barrage

2.1V per cubicle

Galvanising fomite bombardment


Family exit (Japan)


Menage issue (Northwards America)


Menage vent (Europe, Asia, Africa, Australia)


Speedy theodolite tertiary fulminate


High-power wattage lines




What Are Amps?

The amp, frequently cut to “amp” or A, is the groundwork whole of current in the External Scheme of Units. It is named astern the French mathematician and physicist André-Marie Ampère, who is considered the forefather of electrodynamics.

Electricity consists of the menstruum of electrons done a director, e.g., an electrical telegram or wire. We bill the flow of electricity as an current (scarce as we entertain the flow of irrigate in a river as the river stream). The missive ill-used to typify stream in an equality is I.

Current is mensural in Amperes, telescoped to Amps or but the missive A.

A flow of 2 Amps can be scripted as 2A. The larger the flow the more electricity is sleek.

The Outside Scheme of Units (SI) defines amps as follows:

“The amp is that never-ending flow which, if retained in two square duplicate conductors of innumerous duration, of trifling handbill cross-sectional, and set one cadence asunder in a vacuity, would create betwixt these conductors a force-out capable 2×10 −7 newtons per beat of distance.”

Current Demo (Telecasting)

What Are Ohms?

Ohms are the foot whole of opposition in an electric arrangement. The ohm is outlined as “an resistivity ‘tween two points of a director when a ceaseless voltage of one v, applied to these points, produces in the director a flow of one amp, the director not organism the bottom of any emf.” The ohm is named astern the German physicist Georg Simon Ohm.

Resistivity is metrical in ohms, or Ω (z), for brusk. So, 5 ohms can be scripted 5Ω.

In our shelling plot supra, if we hit the lightbulb and reconnected the cable so the bombardment was brusque circuited, the telegram and bombardment would get really hot and the bombardment would presently be matte because thither would be well-nigh no resistor in the tour. Without any impedance, a brobdingnagian electric stream would menstruum until the barrage was vacate.

Erstwhile we add a lightbulb to the tour, resistor is created. Thither is now a local “stop” (or constricting of the shrill, per our calean analogy) where the stream experiences about opposition. This greatly reduces the flow flow in the tour, so the vim in the barrage is released more slow.

As the barrage forces the stream done the medulla, the shelling’s get-up-and-go is released in the lightbulb in the manikin of igniter and rut. In former run-in, the stream carries stored zip from the bombardment to the lightbulb, where it is off into lightness and heat.

The picture supra shows a lightbulb as the chief causa of impedance.

What Are Watts?

A w is the foot whole of superpower in electric systems. It can likewise be secondhand in mechanical systems. It measures how practically vigour is released per indorsement in a organization. In our barrage plot, the sizing of both the potential and the stream in the lightbulb regulate how practically vim is released.

In the plot supra, the bulb would get brighter as the might, deliberate in watts, increases.

We can compute the mightiness released in the lightbulb, and of the electric organization as a unharmed, by multiplying the potential by the stream. So, to cypher watts, the next pattern is exploited.

How to Reckon Watts

W = V * I

E.g., a flow of 2A sleek done a medulla with a emf of 12V crossways it generates 24W of might.

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

If you wish to do an electric figuring involving potential, stream, immunity, or ability, extension the formulae roofy infra. E.g., we can reckon the superpower in watts by referencing the chicken ar in the roach.

This formulae r-2 is really utilitarian for many ee tasks. Donjon it handy the succeeding clock you are dealings with an electric organization.

Beneath are approximately representative equations that are resolved exploitation the formulae.

Representative Equations

1. What is the flow in an circuit with a potential of 120V and 12Ω of immunity?

I = V/R

I = 120/12

I = 10A

The flow in an circuit with a emf of 120V and 12Ω of immunity is 10A.

2. What is the potential crosswise an circuit with a flow of 10A and 200Ω of resistivity?

V = I x R

V = 10 x 200

V = 2000V

The stream in an electric arrangement with 10A and 200Ω of resistor is 2000V.

3 sitejabber reviews. What is the resistivity in an electric organisation with a emf of 230V and a stream of 5A?

R = V/I

R = 230/5

R = 46Ω

The immunity in an electric organization with 230V and 50A is 46Ω.

Formulae round for resolution electric whole equations.


Afterwards indication this clause, you hopefully bear a wagerer agreement of the deviation ‘tween current, potential, opposition, and wattage. Commend that if you cognise any two of the strong-arm values in the formulae roach so you can figure apiece of the former two alien values.

Staple Electricity Tutorial (Tv)

Electricity Test

panorama test statistics

Questions & Answers

Motion: What is the opposition of the warming component of an galvanizing press if the amp tie is 8 amperes when 115 volts are applied?

Reply: R= V/I = 115/8 = 14.4 Amps

Helpful 154

Head: Can I run two appliances simultaneously when the max amps usable is 5A? One requires 3 amp, and the early requires 4.15 amp.

Response: The resolve is no. The summate flow careworn is 7.15 Amps. This would overcharge a 5A socket, and answer in a 5A fuzee blowing or a 5A breaker existence triggered.

Helpful 142

© 2009 Rik Ravado

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *