The use in everyday life of various electrical appliances and devices working thanks to electricity obliges us to have a minimum knowledge in the field of electrical engineering. This is knowledge that saves us life. Answers to questions about how to make an alternating current from direct current, what voltage should be in the apartment and what current is dangerous, a modern person should know in order to avoid damage and death from it.
Ways to get electricity
Today it is impossible to imagine your life without electricity. Every day, the entire population of our planet uses millions of watts of electricity to ensure normal life. But once again, including an electric kettle, a person does not think about which way electricity had to go so that he could make himself a morning cup of aromatic coffee.
There are several ways to get electricity:
- from thermal energy;
- from the energy of water;
- from atomic (nuclear) energy;
- from wind power;
- from solar energy, etc.
In order to understand the nature of the occurrence of electrical energy, consider a few examples.
Electric current is the directional movement of charged particles. The easiest way to obtain it is the energy of natural forces.
In this example, from wind power. People have learned to use the natural phenomenon of blowing with different wind powers for a long time. The wind is tamed by a simple windmill equipped with a drive and connected to a generator. Generator and produces electrical energy.
Excessive current with constant use of the windmill can accumulate in the batteries. The generated constant environmentally friendly current is not used in everyday life and production.
Received and converted to alternating current, it goes for domestic use. Accumulated excess electricity is stored in batteries. In the absence of wind, the electricity reserves stored in the batteries are converted and supplied to human needs.
Electricity from water
Unfortunately, this type of natural energy, which makes it possible to receive electricity, is not always available. Consider a method of generating electricity where there is a lot of water.
The simplest hydroelectric power station, made of wood according to the principle of a mill, the size of which is about 1.5 meters, is able to provide electricity, used for heating, to a private subsidiary farm. Such a damless hydroelectric station was made by Russian inventor, a native of Altai - Nikolai Lenev. He created a hydroelectric station, which two adult men can transfer. All further steps are similar to receiving electricity from a windmill.
They generate electricity and large power plants and hydroelectric stations. For industrial production of electricity, huge boilers are used that produce steam. The steam temperature reaches 800 degrees, and the pressure in the pipeline rises to 200 atmospheres. This superheated steam with high temperature and enormous pressure enters the turbine, which begins to rotate and generate current.
The same thing happens in hydropower plants. Only here rotation occurs due to the high speed and volume of water falling from a great height.
Designation of current and its use in everyday life
Direct current is denoted by DC. In English it is written as Direct Current. In the course of work, it does not change its properties and direction over time. The DC frequency is zero. Designate it on the drawings and equipment with a straight short horizontal dash or two parallel dashes, one of which is dashed.
It uses direct current in the usual batteries and batteries used in a huge number of various types of devices, such as:
- calculating machines;
- Kids toys;
- Hearing Aids;
- other mechanisms.
Every day they use a mobile phone. It is charged through the power supply, a compact DC / AC converter, plugged into a household outlet.
Electrical appliances consume alternating single-phase current. Electrical appliances will only work with the connection of a transformer and a rectifier. Many manufacturers install the DC / AC converter directly in the unit itself. This greatly simplifies the operation of electrical equipment.
How to make alternating current from direct current?
It was said above that all rechargeable batteries, batteries for flashlights, TV remotes, have direct current. To convert current, there is a modern device called an inverter, it will easily make an alternating current from direct current. Consider how this is applicable in everyday life.
It happens that while in a car a person needs to urgently print a document on a photocopy machine. There is a copier, the machine is working and, having included an adapter for the inverter in the cigarette lighter, he can connect a copier to it and print documents. The circuit of the converter is quite complicated, especially for people who have a distant idea of the work of electricity. Therefore, for safety reasons, it is better not to try to build an inverter yourself.
Alternating current and its properties
Leaking, alternating current for one second changes direction and magnitude 50 times. A change in the movement of current is its frequency. The frequency in hertz is indicated.
We have a current frequency of 50 hertz. In many countries, such as the United States, the frequency is 60 hertz. There are also three-phase and single-phase alternating current.
For household needs comes electricity equal to 220 volts. This is the rms ac value. But the amplitude of the current maximum value will be greater than the root of the two. Which in the end will give 311 volts. That is, the actual voltage of a household network is 311 volts. To change direct current to alternating current, transformers are used in which various converter circuits are used.
High voltage power transmission
All electric external networks carry alternating current of various voltages through their wires. It can range from 330,000 volts to 380 volts. Transmission is carried out only by alternating current. This method of transportation is the simplest and cheapest. How to make a constant current from AC, has long been known. Having put the transformer in the right place, we get the necessary voltage and current strength.
The simplest solution to the question of how to make an alternating 220 V from direct current does not exist. This can be done by a diode bridge. The DC / AC converter circuit incorporates four powerful diodes. A bridge assembled from them creates a current flow in one direction. The bridge cuts off the upper bounds of the variable sinusoids. Diodes are assembled in series.
The second circuit of the AC converter is a parallel connection to the output from the bridge, assembled from diodes, a capacitor or filter, which will smooth and correct the gaps between the peaks of the sinusoids.
Perfectly converts direct current to alternating inverter. Its scheme is complex. The parts used are not of a cheap order. Therefore, the price of the inverter is rather big.
Which electric current is more dangerous - direct or alternating?
In everyday life, we constantly encounter at home and at work electrical appliances plugged into sockets. The current running from the electrical panel to the outlet is single-phase alternating. There are cases of electric shock. Safety measures and knowledge of electric shock are necessary.
What is the fundamental difference between getting under voltage with alternating current and direct? There is statistics that alternating DC single-phase current is five times more dangerous than direct AC current. Electric shock, regardless of its type, is in itself a negative fact.
The effects of electric shock
Neglect in handling electrical appliances can, to put it mildly, adversely affect human health. Therefore, do not experiment with electricity, if there are no special skills.
The effect of current on a person depends on several factors:
- resistance of the body of the victim himself;
- the stress that a person has come under.
- from the current strength at the time of contact of a person with electricity.
Given all of the above, we can say that the action of alternating current is much more dangerous than direct. There are experimental data confirming the fact that in order to obtain an equal result in case of a lesion, the direct current should be four to five times higher than alternating.
The very nature of alternating current negatively affects the work of the heart. With electric shock, an involuntary contraction of the heart ventricles occurs. This may cause it to stop. Contact with bare veins is especially dangerous for people with a cardiac stimulant.
For DC, there is no frequency. But high voltage and amperage can also be fatal. Getting out of contact with direct current is easier than getting out of contact with alternating current.
This short review of the nature of electric current, its transformation should be useful to people far from electricity. Minimum knowledge in the field of origin and work of electricity will help to understand the essence of the work of ordinary household appliances, which are so necessary for a comfortable and quiet life.