13.1. System of electric equipment
When checking electric equipment in technical documentation the owner of the car faces the concepts "tension, current and resistance".
Tension is measured in Volts (V), current – in Amperes (A) and resistance – in Ohms (R). In the car tension, as a rule, is meant a concept tension of the rechargeable battery. At the same time about 12 V. Velichina of tension of the rechargeable battery depending on degree of its razryazhennost are about tension of a direct current and from temperature of external air can make 10–13 Century. On the other hand, tension developed by the generator for onboard network with an average frequency of rotation of a shaft of the engine makes about 14 Century.
The concept "current" rather seldom meets in the field of power supply of the car. Current is specified, for example, on a reverse side of safety locks and specifies the maximum current which can proceed without burn-out of safety locks and, therefore, without rupture of an electric chain. Everywhere, where current proceeds, it has to be shunted by resistance. Resistance, among other things, depends on the following factors: cross section of a wire, material of a wire, consumption of current, etc. If resistance too big, then there are functional violations. For example, resistance of wires of high voltage should not be too high, otherwise force of sparks on spark plugs which ignite fuel-air mix sufficiently decreases and, therefore, start the engine.