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An Amp (ampere) is a unit of measurement for electrical current flow. A Watt is a unit of measurement for electrical power. The relationship between current (Amps) and power (Watts) is generally not well understood.

The power (Watts) generated or transmitted by a system is directly proportional to the current (Amperes), and can be expressed in the following equation:

P = IV

Where:

· P is power in Watts

· I is current in Amperes

· V is voltage in Volts

The 'P=IV' equation is correct for all direct current (DC) circuits and for those alternating current (AC) circuits in which the power factor is 1.

When the current or the voltage is not constant, but varies with time t, the correct equation is:

p (t) = i (t) v (t)

Where:

· p (t) is the instantaneous real power in Watts

· i (t) is the instantaneous current in Amperes

· v (t) is the instantaneous voltage in Volts

P = I*V* pf

where

· P is average power in Watts

· I is RMS current in Amperes

· V is RMS voltage in Volts

· pf is the power factor of the load

When the current or the voltage is a perfect sine wave (which they rarely are),

pf = cosine (angle between the voltage and current)

so

P = I*V* cosine (angle between the voltage and current).

The power (Watts) consumed by a purely resistive system is directly proportional to the square of the current (Amperes), and can be expressed in the following equation:

P = I2R,

Where:

· P is power in Watts

· I is current in Amperes

· R is resistance in Ohms.

The power consumed can be much less than the power transmitted. For example, consider a power cable that carries 1,000 Amps at 100 Volts. The power delivered through the cable (P=IV) is 1,000 x 100, or 100,000 Watts. Let's assume the same power cable has a resistance of 0.001 Ohm (1 Milli Ohm) from one end to the other. The power consumed by that cable (P = I2R, which is the electrical power converted into heat) is 0.001 x 10002, or 1,000 Watts. That means there are only 99,000 Watts available after the current flows through the cable.

Now consider an identical power cable, but this time it carries 100 Amps at 1,000 Volts. The power delivered through the cable (P=IV) is 100 x 1000, or still 100,000 Watts. But this time the power consumed by that cable (P = I2R) is 0.001 x 1002, or 10 Watts. In this case, there are 99,990 Watts available after the smaller current flows though the same cable. This is why electrical power companies transmit high power at such high voltages - to reduce the amount of current flowing through the cables, and thus dramatically reducing the power lost to transmission.

See related links below.

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13y ago
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12y ago
Power equals I2RIn a nutshell, the power (measured in watts) dissipated by a resistance is directly proportional to the square of the current (measured in amperes or amps) flowing through that resistance.

It is given by the formula P = I2R, where P is the power in watts, I is the current in amps, and R is the resistance in ohms. For example, if two amps are flowing through a 10-ohm resistor, then the power dissipated by the resistor is 22 * 10 = 40 watts.

See also the Web Links to the left of this answer for more information.

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Another useful equation that looks less scary, omits resistance and instead uses voltage (E).

P = I X E

That 60W light bulb... assuming it is a 120V bulb and your home voltage is also 120V, would be drawing .5 amps (P/E = I)

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15y ago

Appliances will have either a heating element, an electric motor, or perhaps a transformer to step down the voltage for electronic components. These are usually designed for a given voltage, 110v in N America or 240v in most other countries. If a 110v device is connected to 240v, it will take excessive current and probably be damaged. If the reverse is tried, the 240v device may not work at all on 110v.

By Ohms Law, current = voltage/resistance. So if the voltage is doubled, the current will also be doubled. But wattage = (currentsquared) x resistance, so the wattage would be four times as great, leading probably to overheating.

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14y ago

power = voltage * current

Voltage is an energy force that develops the potential power se can see. You can think of it as a water fall. The higher the waterfall, the longer the trip for a water droplet.

Current is the actual water going over the waterfall. If you have only one drop of wate, not much damage if you stand under it. While Niaigra Falls will leave a mark. Moe wate (current) equals more energy.

Voltage is the potential amount of power while current is the kinetic energy actually happening. A battery has a voltage output even when not connected. It takes flow (a circuit) to make that potential energy useful.

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13y ago

The wattage of the device is the product of the amperage times the voltage of the device. The wattage is what you are billed for by the utility company. The higher the wattage the more the device costs you to operate. You are billed by the kWh, which is 1000 of watts per hour. The average cost per kWh is about seven cents. This means that you can use 1000 watt of power for one hour and it will cost you seven cents.

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12y ago

Energy = power * time. For an electrical appliance, there are three operations: active, idling, and off. The off time is not including in the time factor in the equation. The active power is much higher than the idling power. You can use an energy meter to measure the average power of these two modes. A laptop computer consumes about 50 W of power when running, and 0.5 W during standby. So, Energy consumed in a day may be (8 hrs * 50 W) + (8 hrs * 0.5W), assuming the laptop is running for 8 hours and is on standby for 8 hours. The daily energy consumption for this laptop is 0.4 kW-h.

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14y ago

VA is meant as Apparent Power. Formula = V X A [ Voltage X Current]. Watt is a unit of True power Formula = V X A X Cosθ [ Voltage X Current X Power factor].

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13y ago

That depends on the voltage. Amp is a unit of electric current. Watt is a measure of power.

Power = Current * Voltage --> Current = Power / Voltage.

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13y ago

Watts equals volts times amperes.

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10y ago

watts equals volts times amps.

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Q: How are amps related to wattage?
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Related questions

How many volts are in sixty amps?

Amps are related to voltage in the following equation: Watts = Volts * Amps; so in order to answer your question, one would need to know the wattage.


How many amps do you need if you have a 480 volt space heater?

The heater should have a wattage rating (very few list amps). Calculate the amps using the wattage and voltage. Amps = Watts/Volts(480).


How many amps do you need for 2 120 volt lights?

Need to know the wattage to work out the amperage


How much wattage is a 300 ampere welds?

There are zero watts in 300 amps. Watts are the product of amps times volts.


How many amps kW?

Wattage- or kilowattage- is volts time amps. Without knowing the voltage, we cannot answer your questions.


How many amps does an oven draw?

Amps for an oven are governed by the total wattage of the oven and what the voltage supply to the oven is.


How many amps are in a 360 watt vacuum?

If the voltage in your vacuum is 120 then you divide the Wattage by the Voltage to get 3 amps.


What formula can be used to find wattage?

Watts= Volts x Amps


240v 60hz how many amps?

Volts and frequency are two different values. Amps are found by the following formula; I = E/R, I = W/E, I = square root of W/R. None of these formula use 60 Hertz (frequency) in their calculations.In what wattage?Solving for amps is: A=watts/voltsIf you the given wattage and volts then you can compute for amps.Ex. A=120watts/110VoltsA=1.09Amps


What will consume more wattage - a 110 volt appliance drawing 10 amps or a 220 volt appliance drawing 8 amps?

The equation for wattage is W = A x V. Substitute your values into this equation and you will have your answer.


What is the difference between amps and volt-amps?

Amps is a measure of current flowing in a circuit. Volt-Amps or (VA) is a measure of power and is equivalent to wattage for a pure resistive load.


How many amps does a chandelier use?

The amperage that a chandelier draws is based on the amount of bulbs and the wattage of the bulbs used in the fixture. Count the amount of bulbs and multiply that number by the wattage of the bulbs. Take this total wattage and use this formula. I = W/E. Amps = Watts/ Volts.