Electricity lessons: the basics for beginner electricians, current strength and voltage, how to calculate

If any electrical unit fails, the correct solution would be to call a specialist who will quickly fix the problem.

If this is not possible, lessons for electricians will help you fix this or that breakdown on your own.

In this case, it is worth remembering about safety measures in order to avoid serious injuries.

Safety engineering

The safety rules need to be learned by heart - this will preserve health and life while eliminating problems with electricity. Here are the most important beginner electrical basics:

• The first work on networks is best done under the supervision of an experienced electrician.
• It is not recommended to work with high voltage alone. There should always be someone nearby who will insure in case of problems - de-energize the network, call emergency services and provide first aid.
• All work should be carried out with de-energized networks. You also need to make sure that no one connects the electricity during installation.

To perform installation work, you need to purchase a sensor (phase indicator), similar to a screwdriver or awl. This device allows you to find a live wire - when it is detected, an indicator on the sensor lights up. Devices work in different ways, for example, when the corresponding contact is pressed with a finger.

Before starting work, it is necessary to use the indicator to make sure that all wires are not de-energized.

The fact is that sometimes the wiring is laid incorrectly - the machine at the entrance disconnects only one wire, without de-energizing the entire network. Such an error can lead to sad consequences, because a person hopes for a complete shutdown of the system, while some area may still be active.

Types of circuits, voltage and current

Electric circuits can be connected in parallel or in series. In the first case, the electric current is distributed over all circuits that are connected in parallel. It turns out that the total unit will be equal to the sum of the current in any of the circuits.

Parallel connections have the same voltage. In a series combination, the current is transferred from one system to another. As a result, the same current flows in each line.

It makes no sense to dwell on the technical definitions of voltage and current (A). An explanation with examples will be much clearer. So, the first parameter affects how well you need to isolate different areas. The larger it is, the higher the likelihood that a breakdown will occur in some place. It follows that high voltage requires good insulation. Bare joints should be kept away from each other, from other materials and from the ground.

Electric voltage (U) is usually measured in Volts.

More powerful tension is more life-threatening. But do not assume that the low is absolutely safe. The danger to humans also depends on the strength of the current that passes through the body. And this parameter is already directly subject to resistance and voltage. In this case, the resistance of the body is associated with the resistance of the skin, which can vary depending on the moral and physical state of a person, humidity and many other factors. There have been cases when a person died from an electric shock of only 12 volts.

In addition, different wires are selected depending on the amperage. The higher A, the thicker the wire is needed.

Variable and Constant

When electricity was in its infancy, direct current was supplied to consumers. However, it turned out that the standard value of 220 volts is almost impossible to transmit over a long distance.

On the other hand, you cannot supply thousands of volts - firstly, it is dangerous, and secondly, it is difficult and expensive to manufacture devices operating at such a high voltage. As a result, it was decided to convert the voltage - 10 volts reach the city, and 220 volts already get into the houses. The transformation takes place using transformer.

As for the voltage frequency, it is 50 Hertz. This means that the voltage changes its state 50 times per minute. It starts from zero and rises to 310 volts, then drops to zero, then to -310 volts and rises to zero again. All work takes place in a cyclical manner. In such cases, the voltage in the network is 220 volts - why not 310, will be discussed later. Abroad, there are different parameters - 220, 127 and 110 volts, and the frequency can be 60 hertz.

Power and other parameters

Electricity is needed to do some work, such as turning a motor or heating batteries. You can calculate what kind of work he will do by multiplying the current by the voltage. For example, an electric heater with 220 volts and a power of 2.2 kW will consume 10 A.

The standard power measurement is in watts (W). An electric current of 1 ampere with a voltage of 1 volt can produce 1 watt of power.

The above formula is used for both types of current. However, the calculation of the first one has some difficulty - it is necessary to multiply the current strength by U in each unit of time. And if we take into account that the voltage and strength indicators of alternating current change all the time, then you will have to take the integral. Therefore, the concept was applied effective value.

Roughly speaking, the effective parameter is the average value of the current and voltage, chosen in a special way.

Alternating and direct current has an amplitude and effective state. Amplitude parameter is the maximum unit to which the voltage can rise. For a variable type, the amplitude number is equal to the effective number multiplied by √ 2. This explains the voltage indicators of 310 and 220 V.

Ohm's law

The next concept in basic electrical basics for beginners is Ohm's Law. He claims that the amperage is equal to the voltage divided by the resistance. This law applies to both alternating current and direct current.

Resistance is measured in ohms. So, a current of 1 ampere passes through a conductor with a resistance of 1 ohm at a voltage of 1 volt. Ohm's Law has two interesting consequences:

• If you know the A flowing through the system and the resistance of the circuit, then the power can be calculated.
• The power can also be calculated by knowing the effective resistance and U.

In this case, to determine the power, not the mains voltage is taken, but U applied to the conductor. It turns out that if any device is connected to the system through an extension cord, then the action will be applied both to the device and to the wires of the extension device. As a result, the wires will heat up.

Of course, it is undesirable for the connections to heat up, since this is what leads to various disturbances in the operation of the electrical wiring.

However, the main problems are not in the wire itself, but in the various connection points. At these points, the resistance is ten times higher than along the perimeter of the wire. Over time, as a result of oxidation, the resistance can only increase.

The joints of various metals are especially dangerous. In them, oxidation processes are much faster. The most frequent connection zones are:

• Places where wires are twisted.
• Terminals for switches, sockets.
• Clamping contacts.
• Contacts in distribution boards.
• Plugs and sockets.

Therefore, when repairing, the first thing to do is to pay attention to these areas. They must be accessible for installation and control.

By following the above rules, you can independently solve some household issues related to the electrics in the house. The main thing is to remember about safety precautions.