Electricity - the most widely used form of human energy.No exaggeration to say that the definition of an electric current as the orderly movement of electrons is well known even from school physics textbook.But what is the voltage, and how, it is "an ordered movement", not everyone will respond.Recall that an electron, the elementary electric charge, by itself does not move through the conductor.On the other hand, only the movement of the charges along the chain is accompanied by performing useful work in the form of energy conversion from one form to another.It is through these transformations electric current in some cases, the light bulb filament glows, and in others - rotates the rotor motor.In the first case we have the transformation of electrical energy into heat, and in the second - the magnetic.The energy of the moving charges consumed by the source, which supports an electric current in the circuit.Flowing through a conductor, current transfers energy source of EMF to the consumer - the filament windings of the motor, etc.If
determine the amount of charge current flowing through the conductor, it is possible to say that the work depends on the current amount of charge per unit time.But what determines the electric current in the circuit?Consider a model of the current flow on the example of a water jet issuing from the opening in the bottom of the cylinder filled to the top.Imagine that in our model, the cylinder - a conductor, and the water - a large number of droplets of electrons.Then it is clear that the resulting per unit time the amount of water depends on two parameters - the pressure of the water column, which is in electrical circuits, referred to as voltage, and hole diameter - analog electrical resistance.The height of the water column in the model defines the upper potential energy source, drops, charges similar to the flow of electrons that move from the top to the bottom layer.The potential energy of the water mass, ie,the ability to do some useful work on the upper and lower levels are different.Due to the difference in potential, water can flow from the holes and to the conversion of the potential energy of the water column into kinetic energy of the jet of water.If the height of the water column increases, the potential difference or voltage increases, and the current, more accurately, the mass flowing per unit of time water is also increasing.Thus, the proposed model shows directly proportional to the current strength of the voltage.
In the theory of electricity, this conclusion is written as follows: I = f (U) * K, where I - current, U - voltage, and K - individual characteristic reaction circuit for passing current - the conductivity.The technique usually employed reciprocal conduction R = 1 / K, and it is called the "resistance".Resistance is usually treated as the payload chains.In our model, this "resistance" area of the opening acts for the water drain: the larger it is, the greater its cross-country, or the language of electrical conductivity, and therefore, the resistance to water flow is reduced.
on the model clearly shows the potential energy of the stream of droplets, the charge is converted into kinetic energy of the flowing stream.The lower the resistance (or more conductivity), the greater the mechanical work performed on a body of water.In other words, different types of payloads - a current converters, for example, filament converts electrical energy into heat and light, the relay coil converts electrical energy into magnetic energy, etc.
back to electrical circuits, it can be concluded that the current I and voltage U are electrical parameters that determine the operation of the current A (A = U * I).
This current is determined by the amount of the transferred charge, and the voltage is the reason that makes the electrons "orderly" move from larger to smaller capacities.If the voltage is absent, no amount of free electrons in the material will not result in movement of the charges.This means that no voltage does not result in energy transfer.
good demonstration of findings are hydropower plants: they are built using a large level difference (potential) water.Here the mass of falling water similar to the current, and the difference in the levels of the upper and lower pool plays the role of a potential difference.