Making an Electric Current in a Wire
You can make an electric current in a wire if a wire is at right
angles to a magnetic field and the magnetic field is changing. We say
that the electric current has been induced.
You can change the magnetism by moving the wire past the magnet, or
moving the magnet past the wire. It will show up better on a meter if
you use a coil of wire.
A current is generated only when the magnet is moving.
The current stops if the magnet stops moving - even if it is inside
the coil.
The current goes the other way if the magnet moves in the opposite
direction
To make the current greater:
* use more coils
* move the magnet faster
* use a stronger magnet
The magnetic field goes around each loop of wire in the coil, so if
you increase the number of coils there are more places where the
magnetism changes.
The faster the magnet moves, the faster the magnetism changes.
If you keep the magnet still and move the wire, you induce a current
in exactly the same way.
Generators
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Generators induce a current by moving a magnet inside a coil of wire,
or by moving a coil of wire inside a magnetic field. One example of a
generator is a bicycle dynamo.
Bicycles sometimes have dynamos which rub against the back tyre. As
the bike moves, a wheel on the top of the dynamo turns a magnet inside
a coil.
Generators from motors
Simple electric motors generate electric currents when you spin them.
Instead of using electric current to turn a coil, turning the coil
produces an electric current.
Transformers
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Making the magnet stronger and weaker will also produce a changing
magnetic field. You can do this by changing the current in an
electromagnet (the primary coil). If another coil of wire (the
...n on a light switch, press the power button on your computer, or start your car, you are using technology that was invented and pioneered by Nikola Tesla.
...nduced in a conductor moving at right angles to and cutting across a magnetic flux. On the other hand, magnet is a useful in our daily life such as it can hold some documents and use to move an object. For example, a bicycle dynamo is a small generator fitted by bicycle to provide electricity for the lights bulb, it using the principle of electromagnetism. There are 2 law of electromagnetic induction such as Faraday’s Law and Lenz’s Law. In the other hand, Lenz’s Law state that induced current always flows in such a direction so as to opposite the change causing it. When north pole is approach the solenoid, the front part of solenoid will creates a north pole to produce a force of repulsion to oppose the change of motion. And the direction of current in the solenoid can determined by Right-hand Grip Rule. Lenz’s Law also is a form of law of conservation of energy.
This is known as an electromagnet. The current passing through an electromagnet produces a magnetic field. Therefore, the more turns of the coil you have, the greater the magnetic field. and the stronger the electromagnet. This will mean more paper clips.
So Ishrael made the first move. He flicked the switch of his chainsaw. It took a second for the motor to whir to life, for the gears to shift, for the chain of blades to slowly spin. It picked up speed, revolving around like a wheel of a carriage.
...was attached to the disk as well as the galvanometer. As the crank was rotated, Faraday noticed that the needle on the galvanometer moved. Moreover, the needle remained in that condition when the crank was rotated at a constant speed. This device Faraday named the Electric Dynamo (Williams).
F Another wire, or exact same properties (Nickel Chrome, thickness 34). mm and length 30cm) was placed on top of the previous wire, in the same position, both straight and flat. F. The power was turned on again and the same procedure was repeated. recording current and voltage at three points on the variable. resistor.
Michael Faraday was the man behind the discovery of electromagnetic induction. Electromagnetic induction is the creation of an electric current by using a magnetic field. Faraday’s first experiment was set up by coiling to separate lengths of copper wire around a wooden block. The two coils had to be separated he did this with thread. One of the coils was connected to a galvanometer (an instrument used to detect small electrical currents), while the second coil was connected to a battery and switch. As Faraday closed the switch there was a small and brief change in the reading on the galvanometer. What this meant was that Faraday had seen a little and concise current that passed through the galvanometer circuit. Faraday observed the same affect in the galvanometer circuit when the battery circuit was turned off, except the change was in the opposite direction or negative of the first reading of the galvanometer.
Armature - Sometimes called a rotor. This is the part that spins. The armature can be either a permanent magnet or an electromagnet.
... spring, you are causing a twisting motion all the way down the coil. (Longhurst)
First off, what is current. Current is expressed in a unit called Amps. Amps are a measurement of how many electrons pass per second. That is to say, a wire with 40 coulombs passing any point in a 2 seconds would be said to have 20 Amps of current (40 Coulombs (a unit of charge given as 6.24x1018 electrons) / time in seconds or in this case, 2 seconds. The Amp is also known as Coulombs per second) Another trick about current is that it is measured in the movement of the positive charge. Literally that is to say the current moves in oppostion to the electrons. This is because originally it was thought that the positive charge is what moved, both are viable, but in reality a positive charge is generally fixed since within an atom the electrons are migratory, while the protons and neutrons tend to be stationary.
Electric currents produce magnetic fields, they can be as small as macroscopic currents in wires, or microscopic currents in atomic orbits caused by electrons. The magnetic field B is described in terms of force on a moving charge in the Lorentz force law. The relationship of magnetic field and charges leads to many practical applications. Magnetic field sources are dipolar in nature, with a north and south magnetic pole. The magnetic field SI unit is the Tesla, it can be seen in the magnetic part of the Lorentz force law F magnetic = qvB composed of (Newton x second)/(Coulomb x meter). The smaller magnetic field unit is the
Magnets have had a slow and humble start but quickly took off, the discovery of their ability to be affected and effect electrical currents around them. They have been attempted to be used in conventional and nonconventional ways alike from converting energy to relieving pain. We’ve learned that because they are unable to generate their own power we cannot use them as a power source but we can in fact use them for power conversions. I believe further studies in field of magnets will reveal further applications of magnets in the future and quite possibly the application of magnets as a power source.
The phenomenon called electromagnetic induction was first noticed and investigated by Michael Faraday, in 1831. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is a very important concept. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Faraday also investigated the possibility that a current could be produced by a magnetic field being placed near a coiled wire. Just placing the magnet near the wire could not produce a current. Faraday discovered that a current could be produced in this situation only if the magnet had some velocity. The magnet could be moved in either a positive or negative direction but had to be in motion to produce any current in the wire. The current in the coil is called an induced current, because the current is brought about (or “induced”) by a changing magnetic field (Cutnell and Johnson 705). The induced current is sustained by an emf. Since a source of emf is always needed to produce a current, the coil itself behaves as if it were a source of emf. The emf is known as an induced emf. Thus, a changing magnetic field induces an emf in the coil, and the emf leads to an induced current (705). He also found that moving a conductor near a stationary permanent magnet caused a current to flow in the wire as long as it was moving as in the magnet and coiled wire set-up.
In 1831, using his "induction ring", Faraday made one of his greatest discoveries - electromagnetic induction: the "induction" or generation of electricity in a wire by means of the electromagnetic effect of a current in another wire. The induction ring was the first electric transformer. In a second series of experiments in September he discovered magneto-electric induction: the production of a steady electric current. To do this, Faraday attached two wires through a sliding contact to a copper disc. By rotating the disc between the poles of a horseshoe magnet he obtained a continuous direct current. This was the first generator. From his experiments came devices that led to the modern electric motor, generator and transformer.