Not such a rarity when it is required to determine the unknown cross-sectional area of a wire independently. It is simple to make it, and ways exists a little. Unfortunately, to use the simplest of them – never it is almost possible to find out section from marking on isolation: marking either is absent, or is jammed to impossibility. All other ways come down to examination by means of make-shifts.
Instruction
1. It is possible to use for this purpose any available measuring devices. the ideal option is to use a micrometer; it is quite possible to replace it with a caliper. As a last resort, the roulette or a ruler with accurately visible divisions and a pencil will approach (or a long thick nail). It is known that the area of a circle (and wire section – a circle) can be found on formulas S=? r2 or S=0.25? D2; r – wire radius, D – its diameter. Directly sections of the conductor to measure radius difficult and is no need – to determine diameter quite enough. As? =3.14, it is possible to accept that S=0.78D2, – the accuracy of calculations turns out quite acceptable.
2. In other words, to learn cross-sectional area, it is necessary to measure by a micrometer (or a caliper – it is more available) diameter of a vein of a wire, result to increase by itself, the fact that it will turn out – to increase by 0.78. When determining section of wires of large diameter (from 2.5 mm) for simplification of calculations it is possible to use coefficient 0.8. At measurement of wires with a diameter of 0.5 mm it is also less possible to apply coefficient 0.7.
3. In the absence of such precision measuring instruments as a caliper or a micrometer, it is possible to determine diameter by means of a ruler. For this purpose it is necessary to reel up regarding it seems pencil some, for convenience of calculations - multiple to ten, number of rounds of the "studied" wire; what rounds will be more, the end result will be that more precisely. Winding has to be dense, a round to a round. Then it is necessary to measure by a ruler length of the turned-out winding, to divide length into number of rounds, - the result also will be diameter of a vein of a wire. Further it is possible to calculate wire section by the technique described above.
4. It is possible to determine the section of a multicore wire in two ways. In the presence of a micrometer or a caliper the section of one vein is measured, the result is multiplied by the number of veins. To measure the section of a multicore wire by a ruler, it needs to be twisted flat-nose pliers in "braid" and to work further as it is described above.