electricity Flashcards
What is current?
the rate of flow of charge
What are electrons?
negatively charged particles
Where can a current flow?
through a component if there is a voltage across that component
What is the unit for current?
ampere (amp) A
What does the voltage do?
what drives the electrical current through the circuit = electrical pressure
- also called potential difference
What is the unit for voltage?
volt, V
What is resistance?
anything in the circuit which slows the flow down
What causes a higher overall resistance?
if you add more components or the circuit
What is the unit for resistance?
ohm, Ω
What does the ammeter measure?
current in amps
Describe the relationship between voltage and flow
if you increase the voltage, then more current will flow
Describe the relationship between voltage and resistance
if you increase the resistance, then less current will flow
Where should the ammeter be placed?
series
What does the voltmeter measure?
voltage in volts
Where should the voltmeter be placed?
parallel
What are the UK mains electricity supply?
230 volts
What is an a.c. supply?
alternating current, the current is constantly changing direction
What do cells and batteries supply?
direct current
What does direct current mean?
current keeps flowing in the same direction
LED - what is it
light emitting diode - emit light when a current flows through them in a forward direction
used for numbers on digital clocks and in traffic lights
they don’t have a filament which can burn out
LEDs definition
Light-Emitting Diodes
What do LEDs do?
emit light when a current flows through them in the forward direction
What do LEDs indicate?
the presence of current in a circuit
What are LEDs used for? (examples)
numbers on digital clocks, traffic lights and remote controls
