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Electricity. Current Voltage Resistance Current, Voltage, Resistance characteristics AC DC Plugs Earth Fuses Power. Current. Current is the amount of charge flowing past a point in a given time Current (A) = Charge (C) / time (s) Current read by an ammeter – connected in series.
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Electricity Current Voltage Resistance Current, Voltage, Resistance characteristics AC DC Plugs Earth Fuses Power
Current • Current is the amount of charge flowing past a point in a given time Current (A) = Charge (C) / time (s) Current read by an ammeter – connected in series
Potential Difference • Voltage • Potential difference is the energy given to or given by a charge when it passes a component. PD (V) = Energy (J) / Charge (C) PD is taken by a voltmeter and is connected in parallel with the component.
Resistance • Resistance is the volts per amp for a component. • How many volts are needed to push a current of so many through a component. Resistance (Ohms) = PD (V)/ Current (A)
Circuit models • Circuit diagrams • Resistor models
IV Characteristics • Resistor • Bulb • Diode
Resistors • Thermistor • LDR
Mains Elec • PHET • AC DC • Period and frequency
Fuse • A Fuse is a piece of wire with a low melting point • If there is a fault in the electrical appliance and the current goes up it could damage the wiring in the appliance • But if a fuse is installed, this will melt (or “blow”) and break the circuit • So a fuse is used to protect the appliance – not necessarily to protect us from electric shock
Earth • What on Earth does it do? • V d G
Earth • No Earth – No Fault
Earth • No Earth - Fault
Earth • Earth – no Fault
Earth • Earth - Fault
Power • Power = work done / time taken • Lifting stuff
Electrical Power • Electrical power is the electrical work done in a given time. Power (W) = current (A) x voltage (V)