Electricity Flashcards
current
the rate of flow of charge in a current or a solution
rate of electrical charge flow
charge flow = current × time
Q = I t
potential difference
a measure of the electrical work done for every coulomb of charge
iv characteristics
filament bulb
as the temp increases the atoms vibrate more and collide more meaning resistance increase
iv characteristic
diode
current only flows one direction
iv characteristics
resistor
current and potentional difference are directly proptional
thermistor
resistance decreases as temp increases
LDR
resistance decreases as light intensity increases
Series curcuit
- current is the same
- potential difference is shared
- total resitance is the sum of components
parallel curcuits
- total current is sum of current through branches
- potential difference is the same and equal to power source
- the total resistance of the resistors is less than the resistance of the smallest resistor.
domestic energy supply
50Hz
230V
alternating potential difference
the polarity repeatedly changes
direct potential difference
the polarity does not change
in a plug
Live wire
- brown
- carries laternativ potentional difference
- connects to the fuse
in a plug
nuetral wire
- blue
- kept at 0V
- completes the curcuit
in a plug
earth wire
- green and yellow
- a safety wire
- provides low resistance to stop case becoming live
equation
power
potential difference x current
resistance x current2
equation
energy transferred
power x time
charge flow x potential difference
step up transformer
increases potential difference which decreases current
power in = power out
