2 Electricity Flashcards
1
Q
Fuse
A
- Stops appliance from working if current get too high
- Current melts fuse wire
2
Q
Earth wire
A
Provides an alternative route for current to flow down
3
Q
Circuit breakers
A
When a fault occurs, the circuit breaker is tripped, it can then be reset
4
Q
Double insulation
A
- No live conductor can tough the outer casing
- Prevents user from getting shocked
5
Q
Power equation
A
Power (W) = Current (A) x Voltage (V)
6
Q
Energy transferred equaitons
A
Energy transferred (J) = Current (A) x Voltage (V) x Time (s)
Energy transferred (J) = Charge (C) x Voltage (V)
7
Q
Direct Current (D.C.)
A
- Only in one direction
- From + to -
- Low voltage appliances can use D.C.
8
Q
Alternating Current (A.C.)
A
- Current direction changes
- Potential difference (voltage) changes
- Frequency of 50 Hz
- A.C. current is supplied to buildings
9
Q
Plugs
A
- Homes are supplied by A.C. current
- 220V - 240V
Parts: - Live wire: Carries the current
- Neutral wire: Completes the circuit
- Earth wire: Carries no current, there for protection
10
Q
Series circuit
A
- Voltage is shared
- Current is constant
11
Q
Parallel circuit
A
- Voltage is constant
- Current is shared
12
Q
Resistance effect
A
- The higher the resistance the less current flows at a given voltage
13
Q
Resistance factors
A
- Lenght of wire: Longer wire = Greater resistance
- Thickness of wire: Smaller diameter = Greater resistance
- Temperature of wire: More temperature = Greater resistance
- Material of wire: Different materials have a different resistance
14
Q
Heating effect of current and resistance
A
As current flows through wires and components, those with a larger resitance have an increased temperature
- More resistance = More temperature
- More current = More temperature
15
Q
Resistance equation
A
Resistance (Ω) = Voltage (V) / Current (A)
