Inducing a Current by Changes in Magnetic Fields and the Movement of Wires

Inducing a Current by Changes in Magnetic Fields and the Movement of Wires

• Faraday’s Law states that a changing magnetic field can induce a current in a wire. The current is produced by the relative movement of the wire and the magnetic field.
• The size of the induced current can be increased by moving the wire faster through the magnetic field, adding more turns to the coil or using a stronger magnet.
• The direction of the induced current can be reversed by either moving the wire in the opposite direction through the magnetic field or flipping the magnetic field around.
• If the wire forms a closed loop, the induced current can generate a magnetic field that opposes the original magnetic field. This phenomenon is known as Lenz’s Law.
• Alternating current (AC) can be produced by continuously changing the direction of the motion or the magnetic field. This is how generators at power stations work.
• The coil / wire effect on inducing a current is also used in transformers. In these devices, an alternating current in a primary coil induces a current in a secondary coil through a shared magnetic field.
• Transformers are used in the national grid to step up the voltage for transmission to reduce energy loss, and then step it down for safer usage in homes and businesses.
• Electromagnetic induction, which is the process by which a magnetic field induces current, is fundamental to many electrical appliances and technologies, including electric motors, generators, and transformers.
• It is essential to understand the concept of ‘flux linkage’. It presents the overall effect of magnetic field on an area, which is the product of the magnetic field strength, the area through which it passes, and the angle at which it meets that area. A change in any of these three factors will induce a current.
• Whenever you have a current inducing a magnetic field, or a magnetic field inducing a current, it is important to use the ‘right-hand rule’ to determine the direction of either.