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what controls the voltage gauge
The old automobile voltage gauge is mechanical, now we don't mention it. What you're talking about is electronic induction. There is an electronic induction plug on the gearbox. When the car moves, the magnet in the gearbox cuts the magnetic line of force. The induction plug generates current and drives the code meter through the wire (in other words, it's a voltmeter). In fact, it is the voltage of your generator, and then the instrument adjusts the voltage and current between the pointer coils according to the voltage to form a magnetic field, which drives the pointer.
The characteristics and general rules of automobile line wiring are as follows: generally, single line system, parallel connection of electrical equipment, negative grounding, lines are distinguished by lines and numbers with different colors, and divided into several trunk lines centered on the ignition switch.
1.Battery positive wire: lead directly from the battery to the fuse box, or lead directly from the battery positive wire to the positive terminal
of the starter, and then lead the thinner positive wire to other circuits.
2.Ignition, instrument and indicator wires: the circuit can only be connected through the car key.
3.Special line: electrical appliances that need to be connected no matter the engine works, such as radio and cassette player, cigarette lighter, etc., are powered by a separate gear set by the ignition switch.
4.Starting control line: the control switch (contact wheel) of the main circuit of the starter is usually connected and disconnected by magnetic switch. There are three wiring modes: the suction coil and holding coil of the magnetic switch of the low-power starter are controlled by the starting gear of the ignition switch; The attraction and holding coil of high-power starter is controlled by starter relay (such as Dongfeng Jiefang and Mitsubishi Heavy Vehicles)- For cars equipped with automatic transmission, in order to ensure neutral start, the start control line is often connected in series to the neutral switch.
5.Grounding wire: grounding points are distributed in the whole body of the car and form an electrode potential difference with different metals (such as iron, copper and aluminum, aluminum and iron). Some grounding parts are easy to be contaminated with mud, oil or rust, and some grounding parts are very thin sheet metal, which may cause poor grounding, such as the light is not on, the instrument does not work, the horn does not sound, etc. Therefore, some cars use double grounding wires.
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