About the static electricity problem of MacBook Pro series notebook computers - don’t blame Apple
Conclusion: MacBook Pro notebooks do not generate static electricity. Sometimes the human body touches it and the hands are numb. It is because the human body has static electricity and affects the notebook. Caused by discharge of metal casing. Discharge: No harm other than minor discomfort to humans. Many friends who have used MacBook Pro reported that the MacBook Pro was charged, even when connected to a power cord with a protective grounding. After the MA895-897 notebook was launched, the issue of electrification has not been solved.
Isn’t it terrible that your hands will go numb if you touch the notebook? Now it has been rumored by some friends as a defect of MacBook Pro. Apple fans love the house and go to the tiger mountain, knowing that there is a tiger in the mountain. Ordinary users are beginning to wonder whether they should buy this notebook. Will Apple computers be charged with electricity? It's okay if you get an electric shock! ?
According to common sense, it shouldn’t be the case, but I couldn’t tell for the moment. I have never seen or used a MacBookPro. However, after analyzing it with the knowledge of physics and electricity in the past few days, I finally understand what is going on, and I would like to post this to share with you.
First of all, it cannot be caused by leakage of electricity in the laptop. Large international companies have strict quality control and factory inspections. It is unreasonable for a large number of products to leak electricity. Even if there is leakage, the electricity will not be returned after being grounded. Besides, sometimes there is no need for an external power supply and the battery can still power people!
Does the notebook have static electricity? It seems reasonable. Everyone explains it this way. The generation of static electricity has become a defect of MBP notebooks.
No, after an object with static electricity is grounded and the static electricity is discharged, will it still shock people?
In fact, it is very simple. It is not the laptop that has static electricity, but your body that has static electricity!
When the human body is well insulated from the ground and the air is relatively dry, human activities (such as friction with clothing) will generate static electricity, which gradually accumulates to a potential of several thousand to tens of thousands of volts.
For example, when the human body comes into contact with other objects, it will discharge due to different potentials. If you touch someone else, both people will be numb, and you will be shocked if you grab a doorknob. Everyone has experienced this. Of course, it’s not surprising that you get an electric shock when you touch your notebook with static electricity.
No, books from other brands are fine! Is Xiaobai okay? How to explain?
The problem lies in the all-metal casing of the MacBook Pro notebook
(the surface of the aluminum alloy is oxidized after stamping, and the insulation layer is extremely thin). Other notebooks have either plastic casings or metal die-cast frames plus plastic outer frames (for decoration and secondary protection). When a charged human body touches them, the discharge current is relatively small and cannot be felt. The upper and lower metal covers of 15.4-inch or even 17-inch laptops have a relatively large capacitance to the ground. Even if they are insulated from the ground, the discharge will be felt by the human body after contact (the grounding is more severe). Although the plastic case MB061-063 uses the same power converter, there is no static electricity problem, which means it has nothing to do with power leakage. Discharging the case will not affect the internal working of the computer. However, when discharging the external interface of any brand of laptop, although the interface circuit has a strong anti-static ability, it will have adverse effects if the discharge potential is too high. Please develop the habit of not touching the external interface of the laptop with your hands when using it. .
Attachment: There is also a human body current. When the mains power is supplied, the power converter that supplies the power has a step-down transformer (whether it is a switching power supply or an ordinary power frequency power transformer). Although it has Good insulation, but there is a certain distributed capacitance between the primary and secondary coils, and this capacitive reactance can pass alternating current. After the power supply is connected to 220VJ alternating current, if you use a highly sensitive meter to measure it, there will be current (in the order of microamps). This capacitive current is tiny and harmless, and most people will not feel it, but some sensitive people will feel it through such a small current.
Capacitive current may exist in almost all electrical appliances, and even medical equipment with the most stringent safety standards is allowed (safety standards for medical equipment stipulate that leakage current to the ground is 0.5mA, and leakage current from the shell and patient is 0.1mA). If a three-core power socket is used, the primary and secondary coils are isolated and grounded to shunt the capacitor current.