LED electronic screen should never ignore grounding
LED electronic screen is the main component is the LED and driver chip, belongs to the microelectronic products of the aggregate, LED working voltage in 5V or so, the general working current of 20 mA or less. Its working characteristics determine its resistance to static electricity and abnormal voltage or current impact is very fragile. This requires us to recognize this in the production and use of the process and pay enough attention to take measures to protect the LED electronic screen. The power supply grounding is the LED electronic screen is the most commonly used a protection method.
Why should the power supply be grounded? This and the switching power supply mode of operation, LED electronic screen switching power supply is a filter - rectifier - pulse modulation - output rectifier - filtering and a series of means of alternating current (AC220V utility converted to DC (DC5V DC power supply stable) Output of a device.
In order to ensure the stability of the power supply AC / DC conversion, power supply manufacturers in accordance with the national 3C mandatory specifications in the AC220V input side of the circuit design
from the firewire to ground across an EMI filter circuit. To ensure the stability of the AC220V input, so all the power supply in the work there will be filter leakage, a single power supply leakage current of about 3.5mA. Leakage voltage of about 110V display is not grounded, leakage current may not only cause chip damage or lamp burnout. If more than 20 power supplies are used, the cumulative leakage current reaches more than 70mA.
Enough to cause leakage maintainer action, cut off the power supply. This is why my display can not use the leakage maintainer. If not connected to the leakage insurance and the display is not grounded, power supply superimposed leakage current will exceed the human body safety current, 110V voltage is enough to cause death! And grounded, the power supply shell voltage on the human body close to 0 marking the power supply and the human body does not exist between the potential difference, the leakage current is imported into the earth. Therefore, LED electronic screen must be grounded.
