Why cant thousands of volts of electric mosquitoes beat electricity to death?
Date of release:2019-01-11 Author: Click:
Insects are flying in front of us again. If you can't hit it with your bare hands and use insecticides, you can still use mosquito swatters to make it more addictive while listening to the click and smelling the burnt smell. But when we get the instructions of the electric mosquito racket, we can't help but scare out a cold sweat - the output voltage of the electric mosquito racket can reach more than 2000 V. Can an electric mosquito racket be used as an electric baton? Now that this question has arisen, let's see if the electric mosquito racket can actually cause harm to people.
Triple power grid = anti-collision
How does an electric mosquito racket electrocute mosquitoes? First of all, of course, the 220 V AC voltage is changed to 2000 V DC voltage through the function of rectifier and boost transformer inside the mosquito racket. Then the key to the electric mosquito racket is the power grid.
It's not the power grid, it's a real live wire mesh... Looking carefully at the electric mosquito racket network, it is not difficult to find that there are three layers altogether. The upper and lower layers are called the "outer layer" and the middle layer is called the "middle layer". The three-layer grid of electric mosquito racket is actually the two poles of HVDC line, the middle grid is the positive pole, and the outer grid is the negative pole.
There is a distance between the middle grid and the outer grid. The distance is designed according to the voltage of the electric mosquito racket. This distance is very ingenious - when the mosquito racket is stationary or waving, this distance can ensure that the two layers of power grid are insulated and can not form a path (if the distance is too close, the insulation can not be guaranteed); when the insect crosses the outer power grid and contacts the middle power grid, it will break down the air (air gap) between the two layers. It produces an arc and a click (insects cannot break through the arc if they are too far away). This arc is the weapon that kills mosquitoes.
Interestingly, the killer is the power grid, which provides protection for users, but also the power grid. Let's review the appearance of the electric mosquito racket grid again - the outer grid is obviously more sparse than the inner grid. There are also reasons for this:
In order to protect users, the electric mosquito racket puts one pole of the low potential of the power supply on the outer layer. In this way, when users touch the outer layer of the power grid, because of the low potential of the outer layer of the power grid, they will not form a loop with the large area, resulting in electric shock to the human body. Therefore, when people touch the outer grid, they will not be electrocuted. People don't get electric shocks, and insects don't. In order to make insects more accessible to the middle grid, the design of the outer grid is very sparse.
The outer grid is sparse, and there's one drawback --- the human finger can get in. But friends who have had experience in this field all know that when the finger goes in, although it will feel tingling, it will not have a greater impact on the body. (The feeling of electric shock is not good, so remind users to turn off the electric mosquito racket when they do not use it, especially when they have children at home.) So why thousands of volts of electric mosquito racket, electricity does not kill people?
High Voltage + High Resistance = Small Current
As I explained in my previous article (click to see), what makes people feel tactile is the current, which has nothing to do with the voltage. This is just another way to prove that although the electric mosquito racket can produce high voltage, it can only output small current, so it will not cause too much harm to people.
High voltage circuit generates small current. The principle is simple. According to Ohm's law I=U/R, it is known that only one large resistance can be connected in series in the circuit. In fact, the electric mosquito racket does the same thing. It outputs high voltage just to make it easier to break through the air gap and kill mosquitoes, or the current. If you want to electrocute a mosquito, 5 mA of current is enough (the safe current of human body is 30 mA, below which, it will not cause harm to human body).