P5 Flashcards
direct and alternating current
- direct current flows in one direction only
- alternating current repeatedly reverses its direction on flow
mains circuit
has a live wire, which is alternately positive and negative every cycle, and a neutral wire at zero volts
the national grid
nationwide network of cables and transformers
step-up transformers
- used at power stations to transfer electricity to the National grid to consumers
- used to make pd. much bigger
step-down transformers
- used to supply electricity from the National Grid to consumers
-provides same power as 230V
p.d of a.c supply
maximum voltage measured from zero volts
measure freq. of a.c supply
measure time period of the waves
- freq. = 1/time taken for 1 cycle
socket and plug cases
- made of plastic materials that enclose electrical connections
- good electrical insulator
mains cable
- copper wire doesn’t rust
- fuse between live pin and live wire, if too much current passes through the wire it melts and cuts of the live wire
wire colours
- brown wire connected to live pin
- blue wire connected to neutral pin
- green/yellow connected to earth pin
power
current - charge that flows through it each second
- p.d - is the energy transferred to the appliance by each charge that passes through it
- power - energy transferred by electric current each second
domestic appliances
3A, 5A or 13A fuse
energy and p.d
- each electron repeatedly collides with the metal ion of the resister, transferring energy to the ions
- they gain kinetic energy and vibrate more
- resister gets hotter
- chemical energy into kinetic energy
energy transfer in a circuit
energy supplied by the battery = the energy transferred to the bulb + the energy transferred to all the components in the circuit
