P2- Electricity, Circuits, symbols, The National Grid, Power Flashcards
What is Current?
The rate of flow of charge
What is the National Grid?
A giant system of cables and transformers that covers the UK and connects power stations to consumers
What does the National Grid do?
Transfers electrical power from power stations anywhere on the grid to anywhere else on the grid where it is needed.
What is Step-down?
Step-down transformers are used to supply electricity from the National Grid to consumers
What is Step-up?
Used at power stations to transfer electricity to the National Grid. POTENTIAL DIFFERENCE
What is an LDR?
A Light Dependent Resistor which depends on the light intensity. In the darkness the resistance is highest.
What does an Ammeter measure?
Current flowing in Amps
What is the equation linking Current, Charge and Time together?
Q
I X T
What is Charge measured in?
Coulombs - C
What is Current measured in?
Amperes -A
What is the equation linking Current, Resistance and Potential Difference together?
V
I X R
What does a Voltmeter measure?
Potential Difference in Volts
What is a Thermistor?
Temperature Dependent Resistor
cold- resistance up
hot- resistance down
What is a series circuit?
- ALL OR NOTHING
- Everything is connected together, if you remove something none of the circuit works
- The same current flows through all the components
How do you work out the total resistance in a circuit?
Add all the resistance up
What is a parallel circuit?
- INDEPENDENCE AND ISOLATION
- Different routes to take
- Current Splits
- If you remove one part of circuit it could still work.
What is the colour of the LIVE wire?
brown
What does the LIVE wire do?
Provides the alternating current (230v) from the main supply
What is the colour of the EARTH wire?
Green and Yellow
What does the EARTH wire do?
Protects the wiring and safety- stops the appliance casting from becoming live. Doesn’t usually carry a current- only when there’s a fault.
What colour is the NEUTRAL wire?
Blue
What does the NEUTRAL wire do?
Completes the circuit and carries away current. Electricity normally flows in through the LIVE wire and out through the NEUTRAL wire.
What is the formula for Energy Transferred?
E= P X T
What is Power measured in?
Watts
