General information about on-board electrical equipment

When checking electrical equipment in the technical documentation, the car owner is faced with the concepts "voltage, current and resistance". Voltage is measured in Volts (V), current strength - in Amperes (A) and resistance - in ohms (R). In a car, voltage usually refers to battery voltage. In this case, we are talking about a DC voltage of approximately 12 V. The voltage of the battery, depending on the degree of its discharge and on the outside temperature, can be 10-13 V. On the other hand, the voltage generated by the generator for the on-board network at an average engine shaft speed is approximately 14 V.

concept "current strength" relatively rare in the field of vehicle power supply. The current strength is indicated, for example, on the reverse side of the fuses and indicates the maximum current that can flow without blowing the fuses and, therefore, without breaking the electrical circuit.

Wherever current flows, it must be shunted by resistance. The resistance depends, among other things, on the following factors: wire cross-section and material, current consumption, etc. If the resistance is too high, functional disturbances occur. For example, the resistance of high voltage wires should not be too high, otherwise the sparks on the spark plugs, which ignite the air-fuel mixture and therefore start the engine, are sufficiently reduced.