Electrical equipment. General information (BMW 7 Series E32)

When testing electrical system components, it is important to have an understanding of basic electrical terms: voltage, current, and resistance.

Voltage is measured in volts (V), current in amperes (A), resistance in ohms (Ohm). Voltage in a car is usually understood to mean the voltage of the battery (AB), i.e. a constant voltage of about 12 V. The voltage of the AB depends on its charge and the outside temperature and varies from 10 to 13 V. Voltage is also supplied to the electrical system from the generator, and at average speeds it is about 14 V.

The term "current" or "current strength" is rarely used in auto electrics. Current strength is usually indicated on fuses and corresponds to the maximum current that can pass through the fuse without burning it out.

Wherever electric current flows, it is subject to electrical resistance. It depends on many factors, the cross-section of the wire, its material, temperature, etc. The magnitude of the resistance, in particular, has a great influence on the operation of the ignition system.