in each closed circuit compulsorily holds dual energy conversion.In a modification of the current source takes some energy (e.g., generator - machining) into electrical energy, and in the current circuit it is again converted into the amount of energy equivalent to that kind.Measure converting circuit current electricity in any other forms of energy - the value of the current operation.
But we understand that the work and power of electric current is the work of electric field forces, transporting charges;so it is easy to calculate.
work on the transfer of electric charge in the electric field is evaluated the product of the transferred charge on the value of the potential difference between the points at the beginning and end of the transfer, iethe value of the voltage:
A = qU.
Obviously, this ratio may be applicable and to assess concepts such as work and power of electric current.The magnitude of the charge which flowed in the circuit, we can judge by the current flowing in the circuit, and the time of its occurrence as q = It.
Using this ratio, we get a formula that expresses the magnitude of the current work on a separate part of the chain, having the voltage U:
A = UIt.
Work and power of electric current are measured as follows: if to measure the current in amperes, time in seconds, and volts, the work - in joules (J).
Thus 1 Joule = 1 amp x 1 volt x 1 second.
power measured watts (W):
1 watt = 1 joule / 1 second or 1 watt = 1 volt x 1 amp.
issue of calculating the value of the current work in this area is completely unrelated to the question of what kind of energy will become at the site electrical energy.This work is a measure of power, transformed into other forms.
Electric current, performing a job, can heat up the filament bulbs, melting metals, rotate the armature of the motor, cause the chemical conversions, etc.In all cases, work and power of electric current determines the level of power conversion into other forms - mechanical energy, energy of thermal motion, etc.
Knowing that the power P = A / t, you can obtain a formula by which the output current is calculated on a separate part of the chain:
P = UI.
Employment and DC power can be calculated by using these formulas and with the help of an ammeter, voltmeter.In practice, the work of the electric field is measured by a special device - the meter.Passing through the counter, inside starts to make lightweight aluminum drive momentum, and its rotation speed is directly proportional to the current and voltage.Speed, which he will do for some time, will help to draw conclusions about perfect for this time work.Electricity meters can be found in each apartment.
output current is measured using a special device - the power meter.The device of this device combined principles voltmeter and an ammeter.
Many electrical appliances and technical devices indicated their power.For example, the power of incandescent bulbs can be 25 W, 75 W et al., The power of a vacuum cleaner or iron about 1000 watts of electric power may reach very high values - up to several thousand kilowatts.In this mean output current which passes through one or the other device.
Work and AC power are calculated differently.For example, to calculate the work done by alternating current for a certain period of time, you can use the formula:
P = 1 / 2I₀U₀ cos φ.Often, this formula is written in this form: P = IU cos φ, where I and U - values of voltage and current, which is 2 times less than the corresponding amplitude values.
calculation formula AC power is the same as for the DC.
unit of energy and work:
1 Watt-second = 1 J 1 Wh = 3600 J;
hectowatt 1 hour = 360,000 J;
1 kWh = 3600000dzh.
power units:
1 ampere-volt = 1 watt;
hectowatt 1 = 100 W;
1 kilowatt = 1000 watts.
