How do you measure electricity?

Magnetic effect of electricity - you should know that

• Electricity can neither be seen nor heard, but it is "noticeable" through different effects. Among other things, electricity can be used to generate light and heat, but also a magnetic field.
• The famous attempt to do this comes from the Danish physicist Hans Christian Oersted. At the end of the 18th During his experiments with electricity in the early 1900s, he discovered that it could deflect a compass needle.
• This experiment was the basis for the construction of electromagnets, the invention of the electric motor and the generation of alternating current with the help of generators.

Moving coil instrument - this is how you measure current

• Electromagnets and permanent magnets exercise attractive resp. repulsive forces on each other - depending on the polarity of the two magnets.
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• A coil (often with an iron core to reinforce the electromagnetism) wound from conductive power cable is brought in a horseshoe magnet, when the current is switched on, it is directed in the permanent field of the horseshoe magnet the end.


Electric motor - the physics behind it simply explained

Electric motors come in different designs. Physical basis of all ...

• This is the principle by which one measures current with a moving coil instrument. There, too, there is a coil (with current flowing through it in the measurement case) in an external magnetic field.
• However, spiral springs provide a counterforce to the magnetic repulsion or Attraction.
• If a current to be measured flows through the coil, it rotates (since it has become an electromagnet) in the external field until the restoring force of the spiral spring is in equilibrium with the magnetic force is.
• Since the magnetic force is stronger, the greater the electrical current in the coil, the moving coil is suitable for direct measurement of the current strength.
• If the current flows in the opposite direction (or if you swap the connections of the coil), the direction of the magnetic field of the coil changes (swap the poles). The spool now rotates in the other direction. With a moving coil instrument, you basically measure the direction of the current.
• However, a moving coil instrument can only measure the strength of direct current. If the direction of the current changes very quickly, as in the case of alternating current, the coil, as a mechanical indicator, cannot rotate quickly enough. So it shows no current flow, although one is available.
• A number of ammeter devices still in use today, often called ammeters, are still based on this principle.