How to choose a cord
Illiterate selected signal or power cable can not only degrade the performance of the device connected to them, but also to quickly break down or even cause a fire. Industry produces hundreds of varieties of cords, differing design and specifications.
Instruction how to choose a cord
All cords regardless of destination are divided into single-core and multicore. It is not about the number of conductors in the cable, and the number living in one part of the conductor. Stranded wire is resistant to flex, although specifically to abuse it should not be. Connect devices moved during the operation, it should be only such cords. Single-core cables is good for the connection of fixed wiring products. Use single-core aluminum cables are recommended instead of copper. Stranded aluminum cables does not exist.
Some instruments in operation almost continuously moved. These include, in particular, electric and telephone handsets, and in the industry - handles. Their twisted cords attached. They are stranded, and are themselves similarly folded spring.
Devices in which the external structural elements are heated during operation, connect the heat-resistant cords. Such a cable insulation is not made of PVC, and rubber, and the shell fabric is on top of it. But to use such a cable without the need for (together with the instruments, which are the outer surfaces do not heat) can not be: the quality is low, because the rubber seal over time hardens and crumbles. Finding the slightest signs of this, immediately replace the cable, otherwise it may cause a short circuit.
If a signal transmitted by cable with a frequency of several hundred Hz to several tens of megahertz, it must be twisted or shielded. The first is most often used to transmit digital data, the second - for the exchange of analog signals. At frequencies up to several GHz using coaxial cables.
Flat cables whose conductors are arranged in one row, called trains. They are found in the computers, where there are old IDE hard drives standard and floppy drives. More modern trains which are themselves flat conductors (like PCB) can be found in mobile phones. If the unit is a sliding or folding, ribbon cable must be replaced when worn.
Always try to trim any cable properly according to two parameters: the cross section of the operating voltage and insulation. First Pick up the tables, depending on the conductor material and the current strength. Remember that the addition of a multi-core conductor to be cross-section, rather than the diameters of the veins. The second is to be known (with a margin not less than 2) below the voltage between the conductors and between each of them and the ground. Any work on connecting and disconnecting cords produce when they are de-energized, except when specifically stated the contrary in the documentation.