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Electricity - Coggle Diagram

- - - - The rate of energy transfer or the amount of energy transferred per second
      - electrical power depends on
        
        voltage
        
        current
      - power is given by the equation
        
        P=IV
        
        where
        
        V=POtential difference measured in volts (V)
        
        p=power in watts(W)
        
        I=current measured in Amps (A)
    - - Watts= Joules/second
  - - - The wire breaking means that no more current can pass through it
      - the wire heats up and melts
    - - Fuses can come in a variety of sizes
      - Most common fuse sizes
        
        13A
        
        5A
        
        3A
      - The fuse should always have a current rating that is slightly higher than the current needed by the appliance
      - If the fuse current rating is
        
        too high
        
        The circuit won't be stoped in time to prevent all the damage
        
        Too low
        
        It will break the circuit, even if an acceptable current is going through
  - - - work done=energy transfered
    - - potential difference/voltage
      - the amount of time the component is used for
      - current
    - - E= P x t
        
        where
        
        P= power in watts (W)
        
        Power can be calculated with
        
        P=IV
        
        WHere
        
        3 more items...
        
        Power is the rate at which energy is used or transferred.
        
        t=time in seconds (s)
        
        E= energy transfer in joules (J)
  - - - Some of that energy is disupated as heat
    - - Electric hob
      - toasters
      - Electric ovens
      - kettles
      - ELectric heaters
- - - - The electrical current is the amount of charge passing through a component each second
        
        current= charge/time
      - Calculating charge
        
        charge= current x time
        
        Q=IxT
        
        values
        
        I= current--> amps
        
        T= time--> Seconds
        
        Q= charge--> Watts
    - - Current is measured with an ammeter
      - ammeters are connected in series with the other components
  - - - Voltage in energy terms is The energy transferred per unit charge passing between two points
      - If an electrical current passes through a cell they gain energy
      - As electrons move through components in a circuit they loose energy
      - Calculating energy transfer
        
        Energy transfer= charge x voltage
        
        E=QV
        
        values
        
        Q= charge--> measured in coulombs (C)
        
        Charge is the amount of electricity carried by particles
        
        V=voltage--> measured in voltage (V)
        
        E= energy transferred--> measured in joules (J)
    - - Voltage is measured with a voltmeter
      - A voltmeter is placed in parallel with the component being measured
  - - - The higher the resistance, the lower the current
      - The lower the resistance, the higher the current
      - All electrical components (including wires) have resistance
    - - voltage= resistance x current
      - V= R x I
      - Resistance = voltage/ current
      - values
        
        I= current--> measured in amps (A)
        
        R= resistance--> measured in ohms(Ω)
        
        V= voltage--> measured in volts (V)
- - - - This is because the electrons can only follow one path
        
        This means that the number of electrons passing through one point is allways the same
      - The current in a series circuit depends on
        
        the resistance of the components
        
        Increasing the number of components increases the total resistance
        
        More resistance results in less current
        
        the voltage
        
        INcreasing the voltage increases the current
    - - 2 different components
        
        Voltage will be lower for the copmonent with less resistance
        
        Voltage will be higher for the component with higher resistance
      - 2 identical components wil have
        
        the same voltage
        
        The voltage of the power supply will be divided equaly for every component
    - - Disadvantages
        
        Components can't be controlled separately
        
        If one component breaks, the circuit will stop working
      - Advantages
        
        fewer wires required
        
        all components controlled with a single switch
    - - When two or more resistors are connected in series, the total resistance is equal to the sum of their individual resistances
      - R1+R2=R
      - The total voltage is also the sum of the voltages across each of the individual resistors
  - - - branches
        
        The section fo wires between junctions
      - junctions
        
        points where two or more wires meet to form a new branch
        
        Current is always conserved in junctions
        
        This means the amount of current coming in a junction is the same of the current coming out
        
        Current is not always split equally
        
        It will only be split equaly if the components are the same in each branch
    - - This is because currents slipts in junctions
        
        The electrons have different paths to take
    - - Dsadvantages
        
        Hard to control voltage between different components
        
        More wires and more complicated circuit
      - Advantages
        
        If one component breaks the circuit will continue to work
        
        Components can be individual controlled
  - - - Thermsistors
        
        The resistance in a thermsistor depends on its temperature
        
        If tempreature increases
        
        The resistance of the thermistor decreases
        
        If the tempreature decreases
        
        THe resistance of the thermsistor increases
        
        Relationship between temperature and resistance
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2024/07/thermistor-graph.png
      - Light dependent resistor (LDR)
        
        Resistance depneds on the amount of light detected
        
        As light intensity increases, the resistance decreases
        
        As light intensity decreases the resistance increases
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2024/07/ldr-resistance-light-intensity.png
    - - LED
        
        Only allow current to flow in one direction
      - Lamps and light-emitting diodes (LEDs) illuminate (light up) when a current flows through them
      - Useful to indicate current in a circuit
- - - - the IV graph is a straight line which passes through the origin
      - Resistance is constant
      - Components with linear graphs
        
        wires
        
        fixed resistors.
        
        A resisteer that has a fixed value
      - The relationship between voltage and current is directly proportional
      - https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2021/07/2.1.6-Ohms-Law-Graph.png
    - - the IV graph that is not a straight line
      - Resistance is not constant
      - https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2021/07/2.1.6-Linear-Non-linear-elements.png
      - Components with non-linear graphs
        
        LDR
        
        diodes
        
        directs the flow of electricity to one single direction
        
        IV graph for a filament bulb
        
        In the oposite direction the diode has a very high resistance, meaning it doesn't let any current through
        
        Forward bias
        
        The current goes towards the direction of the arrowhead
        
        Increase in current and voltage in the right side of the graph
        
        This shows that resistance is low
        
        Backward bias
        
        The current goes to the opposite direction of the arrowhead
        
        The IV graphs shows a zero reading in current in the left side
        
        This show that the resistance is very high
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2021/07/2.1.6-Diode-I-V-graph.png
        
        Thermsistors
        
        filament lamps
        
        IV grpah of a filament bulb
        
        The relationship between V and I is not directly proportional
        
        The slope of the graphis not constant, showing that the resistance changes
        
        As voltage increases
        
        the resistance increases; the flatter the slope, the higher the resistance
        
        the current increases at a proportionally slower rate
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2020/09/9.2.3-Filament-lamp-IV-graph.png
        
        Resistance increases because
        
        The higher temperature makes the atoms in the filament vibrate more
        
        This increases resistance as it is harder for electron to pass through
        
        Higher currentt causes a higher temperature
        
        since resistance opposes the current, this causes it to increase at a slower rate
    - - Components needed
        
        power source
        
        variable resistor
        
        to vary the current through the circuit
        
        wires
        
        Voltemter
        
        measure the voltage across the copmonents
        
        Ammeter
        
        measure the current going through the components
      - https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2021/08/10.2.4-Investigation-of-Current-and-Voltage.png
      - Variebles
        
        independent
        
        current
        
        The variable resistor is used to change the current flowing through the filament lamp / diode
        
        dependent
        
        voltage
        
        The voltmeter is used to measure the voltage across the filament lamp / diode
      - Recording measurements of current and voltage as the current increases enables an IV graph to be plotted for each component
  - - - variable resistors
        
        Change the resistance depending on the length of the wire
        
        long wire= more resistance
        
        Short wire= less resistance
      - fixed resistors
        
        resistance remains constant
- - - - Damaged insulation
        
        This means the wire is not protected and if someone touches the wire they could get shocked
      - Overheating of cables
        
        If a is too small and there is too much of a current this could lead to the wire overheating
        
        this can cause
        
        melting of insulation
        
        explosion o long wires
        
        fire
      - Damp conditions
        
        it could conduct electricity either causing a short circuit within a device (which could cause a fire) or posing an electrocution risk
  - - - An insulating material is a material that reduces or prevents the transmission of heat or sound or electricity.
      - A wire is made of copper to conduct electricity
        
        To improve safety an insulating material is put around the copper wire
      - Double insulation
        
        WHen there are 2 layers of insulating material around a wire
        
        Double insulation means that an erath wire is not needed as the wire can't touch the metal casing
    - - Electrical apliances normally have metal cases
        
        THis is a risk as if the wire touches the metal case it will become electrified and would electrocute anyone that touches the metal case
        
        An earthing wire is used to prevent this
      - The earthing wire provides a low resistance path through the ground
        
        This means if there is a fault the current will travel through the ground instead of the person
    - - fuses and circuit breakers stop the current if the current is too big
      - https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2021/08/2.3.3-Circuit-Breaker.png
      - A circuit break is better than a fuse because
        
        It works much faster
        
        it doesn't melt or break meaning it can be reused
- - - - When the terminal changes the current changes direction
    - - https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2020/02/ac-dc.png
      - current in the y axis
      - time in the x axis
  - - - THe current travels from the positive terminal to the negative terminal