Induction creates an electric field by changing the magnetic flux density. It may seem complicated at first, but it’s actually quite simple.
- Imagine a horseshoe magnet. Between the two poles of a magnet, the magnetic field lines run parallel.
- Now run the cable that is connected to the voltmeter into the magnetic field. If you move the cable back and forth perpendicular to the field lines, you will see that the meter shows a change in voltage.
- Since you enter the cable into the magnetic field at a certain speed, you also change the speed of the electrons in the field, according to Lorentz’s law. The electrons are now collected at one end of the cable so that a potential difference is created, i.e. voltage.
- You can remember this better with the left hand mnemonic rule. Position your left hand so that your thumb is extended. The index finger should be perpendicular to the thumb. The thumb indicates the direction of electron movement. The index finger indicates the direction of the magnetic field (north to south). The middle finger shows you the deflection caused by the Lorentz force.
- Therefore, any cable carrying current creates a magnetic field. In inductive charging, the conductor is usually placed in a coil that can transfer the charge. Note that if the end device is not equipped with a receiving coil, it will not be able to charge.
- There is also the right hand rule. Stick out your thumb and imagine that you are holding an invisible rod with the rest of your fingers. The thumb indicates the direction of electron movement, while the other fingers indicate the magnetic field.