Induced Potential and Transformers Flashcards
Give two ways that a potential difference is induced in a conductor
Conductor moving relative to a magnetic field
Magnetic field around the conductor changing
What is another name for the generator effect?
Electromagnetic induction
How can the direction of an induced p.d. 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 p.d. or current?
Speed of movement, strength of the magnetic, number of turns in the coil
How does an alternator make use of the generator effect?
Produces alternating current
Which 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 coilswap contacts with the circuit every half turn
When is the induced p.d. produced by an alternator at its maximum?
When the plane of the coil lies parallel 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?
Changes the magnitude of the alternating p.d.
What does a basic transformer consist of?
Two coils of wire wound around an iron core
Why is iron used for the core of a transformer?
Iron is easily magnetised and demagnetised
How does a transformer work?
Alternating p.d. across the primary coil produces an alternating magnetic field in the iron core which induces an alternating p.d. in the secondary coil
How is the ratio of p.d. across the primary coil and secondary coil related to the ratio of the number of turns on each coil?
Ratios are the same
Which type of transformer has more turns on its secondary coil than on its primary coil?
Step-up transformer
