Advice 1: What is the voltage

All electrical appliances are designed for a certain voltageand all power sources are constructed in such a way that they produce the voltage does not go beyond certain limits.
To explain what voltage is different from the current, resistance and power, you can use this analogy. Imagine a pipe, which is attached to a certain pressure of gas or liquid. This pressure - analogue voltage. From the pressure and the cross section of the pipe will depend on the amount of substance passing through a pipe per unit time. Here a section of pipe - the analog of resistance, and the amount of substance passing through a pipe per unit time is equivalent to that of current. At the same time, the trumpet will be allocated in the form of heat a certain power due to friction. This is the analogue of the thermal power released on the current-carrying conductor.
The voltage is measured in volts. This unit of measurement named after the Italian scientist Alessandro Volta, the inventor of one of the types of electrochemical power sources. Called a thousand volts kV million volts - kV. A thousandth of a volt is called a millivolt, million - microvolts.
The voltage is constant and variable. In the second case, it periodically changes polarity with a certain frequency. The alternating voltage has two values: amplitude and current. The first characterizes the amplitude of oscillations and the second equivalent DC voltagethat would at the same load of the same power. The ratio between current amplitude and voltage values depends on its shape. Have a sinusoidal single-phase voltage peak value exceeds the valid number of times equal to the square root of two.
The concept of "dangerous voltage" is not correct. Danger effects of electricity on humans depend not on the voltage, and amperage. Another thing is that the skin has a certain resistance, and therefore dangerous current can occur at a certain voltage value. Skin of different people has a different resistance, it also depends on the mental and physical condition. Therefore, the threat threshold voltage may vary even in one and the same person. At a certain voltage, the leather breaks, and the power is applied much less resistance to subcutaneous layers, which is even more dangerous.
There is also electrical in addition to mechanical tension. It arises in structures in which externally applied mechanical forces. In addition, some constructions may occur at the stage of manufacture of the inner tension. If you make the object of a transparent material and placed between the two polarizers, it is possible to determine the presence of such stresses. And in a figurative sense voltagem is called the stress state of the human psyche.

Advice 2: What is the electric voltage

Voltage is the ratio of the work spent by the system on a moving charge, voltage. In urban power grids use a three-phase network. How to behave when caught in box of the ragged wire, and which can lead to incorrect behavior?
Voltage refers to the energy characteristics of the electric field. There is another definition of the term: it is the ratio of work to the amount of charge transported through a conductor by a certain distance. The unit of electric tension in SI system is volt. It is named in honor of Alessandro Volta, who first in the world opened the cell and got a shock. Sometimes voltage value as the potential difference. For example, at one point the potential is equal to 13 and another to 10 V. Then the voltage between points will be equal 13 – 10 = 3 V.

Record the voltage in practice

Depending on which voltage is applied in a particular system, use one or the other designation. If voltage more than 1000 V, use kV; if more than 1 million IN – MV etc gigavolt, nanovolt, micro volts.

Voltage is measured with voltmeters, which are divided into millivoltmeters, voltmeters, kilovoltmeters, etc.

Three-phase network

The entire energy system of the planet is based on a three-phase network. It carries two kinds of stress: linear and phase. The linear voltage is a voltage between the two conductors, and the phase – between the conductor and the neutral wire, or zero. So when we connect the load in the triangular diagram, the line voltage is equal to phase, and when we connect the load in a star schema, then the linear voltage increases in the square root of three times. Hence such designations three-phase network, or as a 220/380 V 127/220 V. the First number indicates the phase voltage, and the second – linear.
For a General idea of the values of electric voltage at various sites, give them.

Voltage on some objects

The voltage between the electrodes when you remove the electrocardiogram, is 1-2 mV.
AA battery – 1,5 V.
Telephone line – 60 V.
Electric eel – 650 V.
High frequency TV antenna – 1 to 100 mV.
Contact tram line is 550 V.
Storm cloud – 10 gigavolt.

Useful tip: how to behave in the field ragged wire?

When the open wire touches the ground, it may be a step voltage. Up to a point it is not very dangerous. It becomes fatal only when changing the path of movement of electricity in the human body.

Step voltage – the voltage step of one person. The feet are a contacts, and the current moves in a closed circuit leg-leg. This is a dangerous condition, but not fatal, as the heart is tiny part of the electricity. If the current will lead to uncontrollable muscle contractions and the man will fall down, will change the path of current flow and will increase by a step voltage. This is a lethal situation. It is by no means impossible to avoid. For this to get out of the danger zone quickly, but very small steps, since the step voltage is directly proportional to the distance between the points of contact. But it is better to jump on one leg out of the affected area.
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