Home DVD players, high-end TVs, and home projectors all have video cable connectors. There are many video cables, and there are three different color cables. We should have seen them all, and we have VGA cables, DVI cables, and HDMI cables. Video lines are used to transmit video signals. When we buy video lines, we need to correctly identify it. How to buy it? The following small series tells you how to identify.

1, first look at how to identify the quality of PVC jacket.

The surface energy can see that there is a regular “unevenness” in the crimping of the inside net, which means that the processing technology is good and no relative slippage will occur. It is a good cable. The appearance is smooth, can't see the “unevenness” of the compacted net, and the looseness of the sheath is caused by hand. It is a poor cable; check the shielding netting. Is the number enough? Copper wire mesh, check the solderability, tinned copper wire scraping to see if there is copper wire, the hardness of aluminum-magnesium alloy wire is obviously larger than copper wire; the weaving wire is sparse, the distribution is uneven, and the insulation layer is not tightly wrapped. cable.

2, then check the quality of the core.

Diameter - SYV cable is 0.78-0.8mm, SYWV cable is 1.0mm; there is a SYV75-5 core cable diameter of 1.0mm, the characteristic impedance of this cable is certainly not 75 ohms, does not apply to 75 ohms In the transmission system; check the adhesion of core and insulation. Diagonally incise the insulation layer and pull the core wire in the peeling direction to see if the core wire and the insulation layer are covered with the process material; good cable has a large bonding force, and the poor cable does not have any adhesion; longitudinal tensile test. Take one meter cable, peel off the core layer, insulation layer, shield layer, and outer cover, and leave them 10 centimeters long. The method is: two hands hold the adjacent two layers of the cable, pull in the opposite direction; good cable generally does not pull force, poor cable can be easily pulled out without much effort - elevator cable is very important, many so-called "Elevator special cable" has this problem.