Posted by JohnD [71.246.81.71] on Saturday, February 01, 2014 at 10:16:56 :
In Reply to: Re: amp gauge question posted by Sherman in Idaho [72.47.153.112] on Friday, January 31, 2014 at 20:20:54 :
Current running thru a conductor produces a magnetic field surrounding the conductor. The more amps, the stronger the magnetic field.
If you pass a wire thru a coil of wire, and you put a load on the wire., the coil surrounding the wire will produce electricity in direct proportion to the amp load you are asking the wire to carry.
Thus, electricity produces magnetism, and magnetism produces electricity. A gauge has a needle that moves and indicates whatever you print or paint on the face of the dial. What moves the needle is an electric field (magnetism) passing thru a tiny coil inside the gauge. The more voltage you put into this coil, the more the needle moves.
An ammeter is really a volt meter. The volts come from a coil surrounding the battery cable between the battery and the generator or alternator. When the generator pushes amps into the battery, that load creates a magnetic field that is captured by a coil that coverts it to electricity. That voltage is fed to the tiny coil inside the ammeter whose job is to move the needle inside the ammeter.
If this seems complicated, you now know why charging systems are equipped with a voltmeter instead of an ammeter.
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