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Electrical Systems - Coggle Diagram

- - - - electrical wires made of copper since it has lower resistance and good conductor of electricity
    - - increased cross sectional area decreases resistance, more electric charges can flow through
    - - Length increased to increase resistance, electric charges have shorter distance to flow
  - - - resistance of resistors cannot be varied
    - - resistance of resistor can be varied
        
        can be adjusted lower or higher
  - - - effective resistance increases
  - - - effective resistance decreases
- - - - higher power rating means more electrical energy converted in a second
    - - SI Unit - watt (W)
        
        W means J of electrical energy converted to thermal energy in 1 second
        
        1.0 kW = 1000 W
        
        kWh = kW x h
- - - - an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit
      - reduces effective resistance of a circuit, resulting in generation of large current, causing a fire
    - - draws large current, generating heat and melting insulation, causing a fire
  - - - If person touches metal casing, current flows through body into ground
  - - - Earth wire
        
        connected to the ground (0V)
        
        Provides low electrical resistance
        
        connected to metal casing of electrical appliance
      - Fuse
        
        short thin piece of wire that melts when current exceeding its rating flow through
        
        prevent electrical hazard
        
        another fuse with same rating needs to replace it to work again
      - Live wire
        
        high voltage (240V in sg)
      - Neutral wire
        
        (0V)
      - Scenario: If live wire touches the metal casing and appliance is switched on, the current flows from the live wire to the ground. Low resistance results in high current. Fuse will melt to disconnect the circuit or the Earth Leakage Circuit Breaker will trip to disconnect household electricity supply
      - Scenario, electrical fault: Live wire touches the metal casing, electricity will not go to the earth
        
        Switch close 2. Current flows through metal casing to the earth 3. Electrical resistance along wire is very low (close to zero) 4. Current becomes very high and exceed fuse rating 5. Fuse melts 6. Circuit is disconnected from mains
- - - - drive electrical current around closed circuit
    - - Close/open circuit (not necessary)
    - - Provide a path of low resistance for electrical current to flow
- - - - Chemical effect
        
        Extraction of metals
        
        electricity breaks down (decompose) compounds into its elements
        
        eg. aluminium can be extracted from bauxite by passing electricity through molten bauxite in a process called electrolysis
        
        electroplating - coating metals on objects using electricity
        
        Electroplating
      - Magnetic effect
        
        Telephones
        
        iron rod is placed inside a solenoid (coil of wire), current is switched on and iron rod is magnetised, vice versa this is an electromagnet
        
        electromagnet is made by wrapping a coil of wire, allow electric current to flow, electromagnet has north and south magnetic poles and a magnetic field
      - Heating effect
        
        Used in electrical appliance as ee converted to te
- - - - must be connected in series with other electrical components
      - since current flowing through light bulb is supplied by dry cells, it measures current flowing through circuit and not just through light bulbs
    - - check if the flow of electric charge passes through ammeter