Home appliances require direct current, but why do we use alternating current at home?

We know that electricity can be divided into alternating current and direct current. So do you know which type of electricity your home appliances need?

Many people may think it is AC, after all, Tesla's AC beat Edison's DC more than 100 years ago. Unfortunately, this answer is wrong. Most of the home appliances we use now, including LED lighting, all require DC. Wait a minute, isn't the power transmission line at home transmitting AC? Indeed, it is precisely because the electricity entering the home is not the electricity we need, so it must be converted before use, so we will find that the plugs of home appliances are getting bigger and bigger, and the function of this "big plug" is to convert AC into DC. At this point, I can't help but want to complain about the power strip manufacturers. They are really not keeping up with the times. Count 5 electrical appliances and buy a 5-hole power strip, but you can only plug in 3. It's really too crowded.

Since all the electrical appliances in the home require direct current, why is the power supplied to the home alternating current? Why not just switch to direct current?

When people first used electricity, they used direct current, because that was the only type of electricity available at the time. Edison was the one who popularized direct current to every household. As more and more people used electricity, a problem arose: the transmission of electricity. Electricity is lost during transmission due to resistance, and the lost energy is released as heat, which can cause the transmission line to melt. What can be done? There is no other way, except to build more power plants to shorten the distance between the power generation end and the power consumption end.

At this time, there was an employee named "Tesla" in Edison's company. He left the company because of Edison's suppression. Soon after, he invented a new power system, which is alternating current.

The difference between alternating current and direct current is very obvious. The magnitude and direction of direct current will not change over time, while the direction of alternating current is changing all the time. For example, the direction of alternating current with a frequency of 50 Hz will change 100 times per second. What does this mean? It means that direct current cannot change voltage, but alternating current can. And being able to change voltage means that long-distance power transmission can be achieved. The total power of the transmission line is equal to the voltage multiplied by the current, so when the power remains unchanged, the greater the voltage, the smaller the current. Therefore, increasing the voltage can reduce the current.

The loss of a transmission line is equal to the square of the current multiplied by the resistance. It can be seen that as long as the current decreases, the loss will be reduced. Therefore, as long as the voltage is increased, the loss of the transmission line can be reduced, and long-distance power transmission can be achieved.

Edison was panicked. If everyone used AC, wouldn't the power plants he built all over the world be in vain? So he tried to suppress and discredit AC, but he still couldn't stop the wheel of history from moving forward. AC eventually defeated DC. The victory of AC was closely related to the historical environment. At that time, people didn't have any electrical appliances in their homes. Whether it was DC or AC, it made no difference to the light bulbs used for lighting. But now it's different. Home appliances all need DC. So will DC make a comeback?

Although alternating current can transmit electricity over long distances, it is not without its disadvantages.

The reason why AC can transmit electricity over long distances is that it can change voltage, and the reason why it can change voltage is that it can produce electromagnetic induction. It is also because of the existence of electromagnetic induction that electromagnetic induction will generate inductance and capacitance between AC transmission lines and between transmission lines and the earth, thereby generating inductive reactance and capacitive reactance, causing a lot of power loss. So you know why AC transmission lines are built very high, not because they are afraid of the wires hitting people, but only by keeping them away from the ground can electromagnetic induction be minimized and reactive power loss be reduced. Although AC has such shortcomings, it can still transmit electricity after all. Isn't it still stronger than DC? Today is different from the past.

In Edison's time, direct current could not be transmitted over long distances, but now it is different. We have a way to boost the voltage of alternating current at the power generation end, and then use a converter to convert it into direct current for transmission. After reaching the power consumption end, an inverter is used to convert the direct current back into alternating current, and finally it can be reduced in voltage for use.

Direct current has no electromagnetic induction, so reactive power loss can be avoided during transmission, which greatly improves transmission efficiency. my country's coal and hydropower resources are distributed in the northwest and southwest regions, while electricity consumption is concentrated in the eastern region. In order to solve the problem of uneven distribution of energy and power load, my country has implemented the "West-to-East Power Transmission" plan, and this plan adopts long-distance ultra-high voltage direct current transmission. Since direct current can be transmitted over long distances, and electrical appliances require direct current, is it possible for direct current to replace alternating current in the future? We will have to wait and see.

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