motor effect Flashcards
loud speaker
a current in the coil creates a magnetic field
the magnetic field interacts with the permanent magnet generating a force, which pushes the cone outwards
the current is made to flow in the opposite direction
the direction of the magnetic field reverses
the force on the cone now pulls it back in
repeatedly alternating the current direction makes the cone vibrate in and out
the cone vibrations cause pressure variations in the air - which are sound waves
mirophone
pressure variations in sound waves cause the flexible diaphragm to vibrate
the vibrations of the diaphragm cause vibrations in the coil
the coil moves relative to a permanent magnet, so a
potential difference
is induced in the coil
the coil is part of a complete circuit, so the induced potential difference causes a current to flow around the circuit#
the changing size and direction of the induced current matches the vibrations of the coil
the electrical signals generated match the pressure variations in the sound waves
what is a dynamo
dc current generator
what does a dynamo consist of
coil of wire rotating in a magnetic field.
split ring commutator
The maximum potential difference or current can be increased by:
increasing the rate of rotation
increasing the strength of the magnetic field
increasing the number of turns on the coil
how to induce a potentail difference
a coil of wire is moved in a magnetic field
a magnet is moved into a coil of wire
An induced potential difference or induced current will increase if:
the speed of movement is increased
the magnetic field strength is increased
the number of turns on the coil is increased
how does a transformer work
a changing curent is obtained in the primary coilwhich produces a changing magnetic field in the core
this induces and chnging current in the secondary coil
