functional insulation as well as other insulation exists on circuit boards. Typically, the surface environment of a circuit board is determined to be either Pollution degree 3 or pollution degree 2.If the circuit board is mounted in an electrical box and sealed with a solid sealant, the sealing will look as follows: What should be…
The following circuit diagram The current fuse in position F1 is usually connected in series with the line.The photos of the real thing are shown in the following two pictures, the left one is not labeled, the right one shows the location of the current fuse and some other basic information. In the diagram above,…
We are discussing here the second structure of the PTC heating element, PTC heating element structure please refer to the explanation of its definition. How is the creepage distance of the functional insulation at the location of the red circle in Figure 1 determined? We all know that NOTE 1 of TABLE 18 section has…
creepage distance: shortest distance along the surface of insulation between two conductive parts or between a conductive part and the accessible surface. Charges can be propagated in a directional manner through the air, thus forming an current. This is the meaning of clearance. Charges can actually also propagate through the insulating material itself, because no…
clearance: shortest distance in air between two conductive parts or between a conductive part and theaccessible surface. Clearance is a very important concept. In order to understand clearance, we need to say it again that no substance is completely insulated, and air can also conduct electricity. When the voltage is very high, the current will…
functional insulation: insulation between conductive parts of different potential which is necessary only for the proper functioning of the appliance. Functional insulation is set because of the functional needs of the appliance. In electrical products, there must be conductive parts with different potentials (different voltages). If the voltage of all energized conductors in the product…
basic insulation: insulation applied to live parts to provide basic protection against electric shock Generally speaking, a layer of insulation that is in direct contact with a live part can be a common insulating material (such as plastic materials such as PVC and ABS), or it can be air or a distance ( creepage distance) formed…
rated impulse voltage: voltage derived from the rated voltage and the overvoltage category of the appliance, characterizing the specified withstand capability of its insulation against transient overvoltages. For beginners, it is not really necessary to understand the physical meaning of this definition. The main use of this voltage value in the standard is to determine…
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