3.3- Keeping Things Moving Flashcards
What happens when a current flows through a wire?
A magnetic field is formed around the wire
Motor effect definition
The effect that occurs when a current-carrying wire in the presence of a magnetic field experiences a force
Use of the motor effect
Electrical motors
How is the force increased in the motor effect? (2)
> increase strength of magnetic field
>increase size of current
When will the conductor not experience a force in the motor effect?
When it is travelling parallel to the field lines
When is a voltage induced across a conductor?
When it cuts a magnetic field
When is a voltage induced across a coil?
When a magnet is moved into a coil
What is the core of a transformer made form?
Iron
How does a transformer work?
Alternating current in the primary coil produces a change in magnetic field in the coil and therefore the secondary coil. This then causes a voltage to be induced on the ends of the secondary coil
Which transformer has a higher voltage induced in a step-up transformer?
Secondary (opposite for step-down)
What transformers operate between 50kHz and 200kHz
Switch mode
Pros of switch mode transformers
Lighter and smaller than conventional transformers and use less power
Uses of switch mode transformers
Mobile phone chargers
