Faradays law of induction * A changing magnetic field will induce an EMF in a loop of wire * EMF- electromotive force => elektromagnetisk induktion => Which Is what causes electrons to move and form a current * changing the area of the loop of wire induces a current, too, and so did changing the angle between the loop and the magnetic field. Magnetic flux- magnetisk flödestäthet => a measure of the magnetic field running through a loop go wire. => when the field changes it induces an EMF BxAxcos0= 0b=> magnetic flux alternative: BxA=0b * if the magnetic flux through a loop of wire decreases over time, the EMF increases accordingly. * if the magnetic flux increases over time, the EMF decreases EMF= -number of loops x change in flux/ change in time * Faradays law of induction lets us calculate how much EMF and therefore, how much current will be induced in a loop of wire by a change in magnetic flux. \ \ Lenzs law => says that the magnetic field generated by the induced current will be in the direction opposite the change in magnetic flux. \ Eddy current- virvelströmmar * Lenzs law \ alternators and dynamos * Direct current - alternate current => electrons flow in only one direction => electrons change their directions * an ==a==lternator uses magnetic fields to create @@al@@ternating currents. two commutators * a dynamo uses magnetic fields to create a direct current. one split commutator * Change the size of the magnetic field then the size of the current increases => also happens if we increase => the number of turns => the area of the coil * changing the rotation speed leads to increase in both size and frequency of the current. \ \ Transformers * consists of two or more coils of wire wrapped around the same magnetic field. * If a DC current passes through then the transformer behaves the same way as if they were replaced with normal wires * if an AC current passes through one coil causes current to also flow in the other coil. * Depending on how many turns are in each coil, the transformers can mak the voltage bigger or smaller => more turns=> higher voltage→more energy per particle =>less turns=> lower voltage→ less energy per particle * the transformers does not create or destroy energy it only moves the particles from one side to another * the number of charged particles flowing each second is what we refer to as the current * lower voltage <=> higher current * Higher voltage <=> lower current \ \ \ \
Knowt
Note
Studied by 8 people
