P4 - Electricity Flashcards
Static
Electrons scraped off when two insulators rub
Attract
Uses of static electricity
Paint sprayers -each paint drops repels
Dust precipitators clean emissions
Defibrillators
Charge
It
Pd
Work done/ charge
Energy
Power x time
Charge x pd
Electromagnetic induction
The creation of a potential difference across a conductor which is experiencing a change in magnetic field
What factors affect size of induced voltage?
Strength of magnetic field
Cross sectional area
Number of turns
Speed of movement
Flemings right hand rule
Direction of current
Thumb = motion
First finger fuel
Second finger current
Step up transformers
More voltage
More turns on secondary coil
The transformer equation
Pd primary / pd secondary = number of turns 1/ number of turns 2
Switch mode transformers
Operate at higher frequencies than normal transformers
Smaller
Used in mobile phone chargers
More efficient
Insulating transformer
Used in bathrooms
Same number of turns in primary and secondary
Decreased risk of getting electrocuted
