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sec 2 Electrical Systems (Chapter 13) - Coggle Diagram
sec 2 Electrical Systems (Chapter 13)
Current, Voltage & Resistance
Current (I)
Flow of electric charge
Unit: Ampere (A)
Measured by ammeter (series)
Conventional current vs electron flow
Voltage / Potential Difference (V)
Work done per unit charge across a component
Unit: Volt (V)
Measured by voltmeter (parallel)
Electromotive Force (e.m.f.)
Work done per unit charge by the source around complete circuit
Resistance (R)
Opposition to current flow
Unit: Ohm (Ω)
Circuit Diagrams
Symbols → cell, switch, bulb, resistor, ammeter, voltmeter(refer to notes in sci sec 2 g2 gc)
Types
Series circuit
Parallel circuit
Effects of Electricity
Chemical Effect
Electrolysis
Electroplating (e.g. medical instruments, implants)
Magnetic Effect
Current-carrying coil around iron nail → electromagnet
Increase strength: more turns / higher current
Heating Effect
Stronger when:
High resistance wire (tungsten)
Higher current
Coiled filament
Applications: toaster, oven, heater, fuse
Hazards of Electricity
Damaged insulation → fire/shock
Overloading sockets → overheating, fire
Foreign objects in sockets → electric shock
Wet conditions → water conducts electricity → shock
Safety Features
3-pin Plug
Live wire (brown) → carries current into appliance
Neutral wire (blue) → carries current back
Earth wire (green/yellow) → directs leakage current to ground
Fuse
Thin wire melts when current > rating
Breaks circuit, prevents overheating
Circuit Breaker
Cuts off current automatically
Found in consumer unit
Reusable (unlike fuse)
Double Insulation
Two layers prevent casing from becoming live
Power, Energy & Cost
Power (P)
Energy converted per unit time
Unit: Watt (W)
Reduce Energy Consumption
Use energy-efficient appliances (energy label with ≥ 3 ticks)
Switch off when not in use (standby mode still consumes electricity)
