Voltage is measured in Volts (IN), current strength - in Amperes (A), and the resistance is in ohms (Ohm). In automotive engineering, voltage is usually understood as the voltage of the battery. In this case, we are talking about a DC voltage of approximately 12 V. The magnitude of the battery voltage depends on the degree of its discharge and on the ambient temperature. The battery voltage can fluctuate between 10-13 volts. The voltage for the on-board network is generated by the generator. At medium engine speeds, it is about 14 V.
The concept of current strength in automotive technology occurs relatively rarely. The current strength is affixed, for example, on fuses. The amperage indicates the maximum current that can flow through a fuse without causing it to blow and without breaking the electrical circuit.
Wherever current flows, it must overcome resistance. The resistance, among other things, depends on the following factors, namely: the cross-section and length of the conductor, its material, the current consumed, etc. If the resistance is too high, it may cause a malfunction. For example, the resistance of the high voltage wires of a gasoline engine should not be too high, as in this case, the spark plugs will not be able to generate a strong enough ignition spark to ignite the air-fuel mixture, thereby leading to the engine starting.
Attention! Be sure to disconnect the negative terminal of the battery before starting work on the electrical system. Work on the electrical system is considered to be the simplest disconnection of the electrical wire.