Transformers Flashcards
Give two ways potential difference is induced in a conductor
Conductor moving relative to magnetic field
Magnetic field around the conductor changing
Another name for generator effect
Electromagnetic induction
How can direction of indices pd. Or current be reversed
Reverse the movement of the conductor or magnet
Reverse the polarity of the magnet
What effects the size of an induced pd or current
Speed of movement
Strength of magnetic field
Number of turns on coil
How does an alternator make use of the generator effect
Produces an alternating current
What kind of current is produced by the generator effect in a dynamo
Direct current
How does a dynamo keep the current flowing in the same direction
A split ring commutator makes the ends of the coil swap contacts with the circuit every half turn
When in the induced pd produced by an alternator at its maximum
When the plane of the coil lies paralell to the magnetic field lines
How does a microphone use the generator effect
Converts pressure variations in sound waves into variations in electrical current
What does a transformer do
Changed the magnitude of the alternating current
What does a basic transformer consist of
Two coils of wire wound around an iron core
Why is iron used for the core of the transformer
Iron is easily magnetized and demagnetized
How does a transformer work
Alternating pd across the primary coil produces an alternating magnetic field in the iron core which induces an alternating pd in the secondary coil
How is the ratio of pd across the primary coil and secondary coil related to the ratio of the number of turns on each coil?
The ratios are the same
Vp divided by Vs equals Np divided by Ns
Which type of transformer has more runs on its secondary coil than its primary coil
Step up transformer
