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Physics Topic 2 Electricity - Coggle Diagram
Physics Topic 2 Electricity
Series and Parallel Circuits
Parallel
: A circuit with two or more branches. each component has their own branch so if one is removed it won't effect the rest.
Potential Difference
: V=V1=V2= etc (all the same pd)
Current
: I=I1+I2+etc (add all)
Resistance
: If you have two resistors then the pd is less than the smallest resistor.
Series
: A circuit with one loop. If one component is removed then the whole circuit will stop because the circuit isn't complete.
Resistance
: R=R1+R2+etc (add them all)
Potential Difference
: V=V1+V2+etc
Current
: I=I1+I2+etc
Resistance
Anything in the circuit which reduces the flow of current
V= IR
Unit: Ohms
Current
Flow of electric charge. Flows from positive to negative around a circuit.
Q= It
Unit: Amps
Potential Difference
Electrical charge will only flow around a complete circuit if there's potential difference. It is the driving force for the flow of charge.
Unit: Volts
Ohmic Conductors
At a constant temperature, current and potential difference are directly proportional.
Filament lamps
As the current increases the pd increases.
Diodes
Current flows when pd flows forward. very high resistance in reverse.
Domestic Uses
3 Pin Plug
Live Wire
Carries pd from mains supply. Pd is 230V
Neutral
Completes the circuit. Pd 0V
Earth
Only carries current if there's a fault. For safety. Pd 0V
Thermistor
Type of resistor. Depends on temperature. In hot conditions, resistance drops.
LDR
Depends on light intensity. In bright light resistance falls.
AC and DC
AC= alternating current
Current always changes direction. From a generator.
DC= direct current
Current remains in one direction. From a cell or battery.
National Grid
generates electricity for the UK.
Step up transformers
Increase voltage, decrease current. Increases efficiency decreases heat loss.
Step down transformers
Decrease voltage, increase current. Makes it safe for use in homes.
Static Electricity
Electrical charge is stationary. When two insulating materials rub together the electrons move from one material to the other.
Shocks
When walking on carpet electrons move to the person and charge builds up. When the person then touches metal a spark is made.
Electric Fields
Charged objects create electric fields around them. It's strongest closer to the object. The field strength is the direction of force on a positive charge. Add more charge for a stronger field.
More Equations
Charge= Current X Time
Power= Potential Difference X Current
Power= (Current)2 X Resistance
Energy Transferred= Power X Time
