Topic 2 Electricity Flashcards
(50 cards)
Total resistance =
R1 + R2 etc.
What colour is the earth wire and what does it do?
Green and yellow, safety wire to stop the appliance becoming live, at 0V if running smoothly
What colour is the neutral wire and what does it do?
Blue, completes the circuit, around 0V
What colour is the live wire and what does it do?
Brown, carries the alternating potential difference from the supply, p.d. between live and earth wire is 230V
What is the cells function and symbol? 1
pushes the electrons around a complete circuit
What is the switches function and symbol? 2
enables the current to be switched on or off
What is the bulb/lamps function and symbol? 3
emits light
What is the fixed resistors function and symbol? 4
limits the current in a circuit
What is the variable resistors function and symbol? 5
allows current to be varied
What is the fuses function and symbol? 6
will melt and break if the current is too strong
What is the diodes function and symbol? 7
allows current in only one direction
What is the LEDs function and symbol? 8
emits light
What is the LDRs function and symbol? 9
decreases in resistance as light intensity increases
What is the thermistors function and symbol? 10
resistance depends on temperature
What is the ammeters function and symbol? 11
measures flow of electrons (current)
What is the voltmeters function and symbol? 12
measures electric potential difference (voltage)
Define current
Current is the rate of flow of charge
Charge is measured in …
Coulombs (C)
Current is measured in …
Ampere (A)
Potential difference is measured in …
Volts (V)
Resistance is measured in …
Ohms (Ω)
What is ohm’s law?
Ohm’s law states that the current flowing through a wire is directly proportional to the voltage across it (if the temp remains constant)
Define resistance
It is a measure of the opposition to the current flow in an electrical circuit
As length of wire increases, potential difference _________, current __________ and resistance ________.
increases, decreases, increases