electricity Flashcards
what is the electrical current?
the flow of electrically charged particles (electrons)
sources of potential difference
a cell
batteries(multiple cells)
electrical generator
what does electrical charge need to flow?
it must include a source of potential difference
the two ends of the cells
one end=postive
the other end=negative
potential difference is the same as…
voltage
measured in volts
where is the voltmeter set
parallel to the compenent whose voltage is getting measured
what does a straight line between components in a circuit diagram represent?
connection (wires)
what is current measured in?
amperes
what is charge measured in?
coulombs
series circuits:
it has no branches. the current can only flow in one direction and it is the same all the way round the circuit
parallel circuits:
contains branches
the current in the branches adds up to the total current in the circuit
what is voltage?
is the measure of the difference in energy from one point of the circuit to another
what is resistance?
is a measure of how difficult it is for the charge to flow
the smaller the voltage the easier it is for the charge to flow
what does mA mean?
1/1000 of an ampere (miliamperes)
what is ohms law?
is the current through the conductor directly proportional to the voltage across it
what is direct potential difference?
it is a constant potential difference and only flows in one direction
for example batteries
what is alternating potential difference?
it is potential difference that changes its direction regularly
for example power stations
what is the live wire?
covered in brown plastic
it carries the 230v alternating current from the power supply
what is the neutral wire?
covered in blue plastic and it completes the circuit from the appliance back to the supply
usually at 0V
what is the earth wire?
covered in yellow and green plastic
0V and does not form some of the circuit
there for safety
how does the earth wire protect us?
it produces a low resistance path for fault currents to flow to the ground preventing the current flowing through to the person
what is a fault?
breaks the circuit if a fault in an appliance causes too much current to flow.
why is the live wire dangerous when the circuit is open?
