In a sense, this modern technology-dependent civilization survives on electricity. That has been possible because of the once mysterious and dangerous electricity being tamed. Yet the risks of electricity have not been completely eliminated. There is still a risk of getting a terrible electric shock with a little carelessness. It can even cause death.
It is surprising to think that batteries also have electricity. That electricity is now used to run everything from mobile phones to ordinary household electrical appliances to electric cars. But we usually do not get electric shocks from batteries! When changing the battery of the remote, we freely touch the two ends of the battery, but many people may feel a pang of fear when they try to insert the plug into the wall socket. What is the reason for that? In answer to this, our idea of electricity is actually wrong. Be careful! Batteries can also be dangerous.
Before explaining that, it is important to know that the electricity stored in batteries is called DC or direct current. This electricity can be compared to a calm river, which always flows in one direction. It has no waves, no vibrations. The electricity that comes out of the battery actually goes straight from the positive end to the negative end. The electricity that is stored in the battery is called DC or direct current. This electricity can be compared to a calm river, which always flows in one direction. It has no waves, no vibrations.
And the electricity that is brought to the house by pulling it is AC or alternating current. This electricity is much like the waves of the ocean. It does not move steadily, but rather moves back and forth many times per second (50 times in Bangladesh). Because of this change in direction, it is called alternating current.
In daily life, we use most of the DC-powered electrical devices. Such as mobile phones, laptops, electric cars. Again, even though TVs and refrigerators are connected to AC electricity, they actually run on DC electricity. I will talk about that later. However, the electricity used for these devices is usually of relatively low voltage.
The human body has a kind of natural resistance or resistance. Especially if the skin is dry, the resistance is also high. The resistance of dry skin can be about 10 thousand to 100,000 ohms. On the other hand, the electrical line in the house is AC. And its voltage in Often in the country is 220 volts. If the current enters the body at this voltage, a severe shock is felt, muscles are affected, and even death can occur. As a result, we have this idea that AC means danger, and DC means safe.
But this idea is actually wrong. In reality, the criterion for danger is the voltage, not the type of current. In fact, battery or DC electricity can also become dangerous. In many cases, it is even more dangerous than AC electricity. If the voltage of the battery or DC is more than 50-60 volts, DC electricity can become dangerous.
AC current changes direction 50 times per second (50Hz). This fluctuation causes the muscles in the human body to contract and expand. As a result, an AC electric shock can knock you out. But DC current flows in one direction. If it is high voltage, it will hold the muscles of the body tightly in one place. Therefore, high voltage DC electricity is much like a python, once it holds, it tightens or locks the muscles. As a result, it becomes difficult to release the hand. This increases the risk of burning the body. That is why engineers take utmost care when working with solar panels or electric car batteries.
How electricity hurts people
Electric shock is a complex physical phenomenon. When electricity flows through the human body, several things happen at once. Muscles contract involuntarily, the nervous system is disrupted, the normal rhythm of the heart can be disrupted, and heat can be generated inside the body and tissue burns.
At the root of all this is current, that is, how much charge is flowing through the body every second. Medical scientists have observed that a current of just 1 to 5 milliamperes causes a slight tingling sensation in the hands. 10 to 20 milliamperes causes muscle spasms. When a current of 100 milliamperes or just one to ten amperes passes through the chest, the heart starts to tremble irregularly, which is called ventricular fibrillation. And this is the cause of most deaths from electrocution. Now the question is, how is the amount of current that will enter the body determined?
According to Ohm’s law, current = voltage ÷ resistance. As mentioned earlier, the resistance of the human body is about 100,000 ohms in a dry state and drops to only a few thousand ohms in a wet state. This calculation shows that the higher the voltage, the more current will flow through the body. So the real determinant of danger is voltage.
Think of a solar panel system. Even in a simple solar installation used at home, 300 to 600 volts DC can be generated by connecting the panels in series. Electric vehicle battery packs operate at 400 to 800 volts DC. When this voltage is applied directly to the body, a current of 3 to 6 milliamperes can flow through a dry body. This increases tenfold in a wet or sweaty body enough to stop the heart.
