At amateur designing, transformers with unknown parameters are quite often used. In this case there is a need to define windings of the transformer and their characteristic, in particular, number of rounds.

The concept a material point came to us from physics. The nature has no natural material points, this concept from area of abstraction. For calculation of the done way, it is possible to present the car as a material point because its scales it is incomparable are small with scales of the passable distance.

In coils of windings of excitement there can sometimes be mezhvitkovy short circuits. As the reason of this malfunction of coils serves mechanical damage of a winding or destruction of isolation when overheating. Reduction of resistance of a chain of a winding results that, in turn, increases current. Temperature of a winding increases and leads to short circuit of a bigger number of rounds of the coil. Therefore it is necessary to reveal existence of short-circuited rounds as soon as possible.

The far-sighted and qualitative optics is necessary for any car. It is possible to strengthen lighting own hands, having established biksenonovy a lens. For this purpose a few skills and simple tool kit are required.