electricity Flashcards
Current
voltage
resistant
rate of flow of charge
what drives the current round the circuit
resistance is anything which slows the circuit down
how does resistance work
colliding with ions in the resistor makes it more different for current to flow.
LED’s
emit light when a current flows through in them in hte froward direction.
what is mains supply
alternating current batteries are dc
equation for voltage
current x resistance
LDR
in a bright light the resistance falls
these are useful in things like burglar detectors
what are and what do hte different wires do in a plug
live wires brown coloured are at 230 V
neutral blue wire at 0V
earth wire grreen and yellow
how does an earth wire and fuse work
earth wire connects to a metal casing
a fault develops where the live wire touches the metal casing
earth wire provides a low resistance path fo the current to flow to earth and produces a high current
all currrent flows through fuse in the live earth wire
high current
alternatives to fuses
circuit breakers
double insulation, putting plastic around the whole of the application as plastic is an insulator.
witres
neurtal wire is blue
earth wire is for safety green or yellow
live wire is blue
what does it mean for a wire to be earthed
reduces the danger of an electric shock , all metal cases must be earthed to reduce the danger of obtaining an electric shock, if appliance has a plactic casing it is double insulated.
earth wire provides fastest route to earth
flows from the case of the wire to the ground if there is a fault
how does a resistor work
the electrons collide within the material of the atom
direct and alternating current
direct flows in one direction
alternating flows back and forth
current
rate of flow of charge
why is current the same at junctions
because charge is conserved and current measures the rate at which charge os flowing
