Flashcards in electricity Deck (54)
what is electric current?
Electric current is the flow of electrical charge
what is current measured in?
what is electrical charge measured in?
electrical charge equation:
charge flow = current x time
what is the resistance of a component?
Resistance of a component is the measure of how it resists the flow of charge
the higher the resistance:
- the more difficult for charge to flow
- the lower the current
what is resistance measured in?
what does potential difference tell us?
potential difference tells us the difference in electrical potential from one point at a circuit to another
the bigger potential difference across a component:
-the greater flow of charge through
-the bigger the current
what is potential difference measured in?
potential difference equation
potential difference= current x resistance
what does a current graph show?
a current graph shows the relationship between potential difference and current for any component
straight line graph
(resistance remains constant)
filament lamp graph:
indicated by a curved graph
(resistance increase as current increases)
horizontal line along x axis
(no current flows)
what happens to the resistance of a thermistor?
The resistance of a thermistor the decreases as the temperature increases
what happens to the resistance of an LDR?
The resistance of an LDR decreases as light intensity increases
what happens in a SERIES circuit?
in a series circuit:
current: STAYS the same
potential difference: SHARED
what happens in a PARALLEL circuit?
in a parallel circuit:
potential difference: NOT shared
what happens if a component in a SERIES circuit breaks or is removed??
the rest of the components WILL NOT work
what happens if a component in a PARALLEL circuit breaks or is removed??
the rest of a component WILL continue to work
what does the power of a device depend on?
The power of a device depends on the potential difference across it and the current flowing through it.
a device with higher potential difference will....
use more energy per second
2 equations for POWER
power= potential difference x current
power=(current)2 x resistance
DIRECT current potential difference:
-one is always positive or always negative
-> makes current constant
when is DIRECT current used?
direct current is supplied by cells and batteries
ALTERNATING current potential difference:
-alternates from positive to negative
-> makes current direction alternate
when is ALTERNATING used?
alternating current is used in mains electricity
what colour is live wire?
love wire is brown