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Electricity - Coggle Diagram

- - - - Must be converted from the primary energy sources
        
        Examples
        
        Solar Energy
        
        Wind
        
        Water
        
        Fossil Fuels
  - - - Electric Cells
        
        Use
        
        Supply a large amount of electricity to households and industries
        
        Energy Transformation
        
        Kinetic energy ---> Electrical energy
        
        Potential energy ---> Electrical energy
        
        Examples
        
        Windmills or wind turbines
        
        Power stations
      - Electric Generators
        
        Use
        
        Supply a small amount of electricity to portable electrical devices
        
        Energy Transformation
        
        Chemical energy ---> Electrical energy
        
        Examples
        
        Dry cells
        
        Lithium cells
        
        Lead-acid accumulators
      - Solar Cells
        
        Use
        
        Supply electricity to specific devices such as satelites or calculators
        
        Energy Transformation
        
        Solar energy ---> Electrical energy
        
        Example
        
        Solar panels in calculators and photovoltaics
  - - - Light energy
      - Heat energy
      - Chemical energy
      - Mechanical energy
    - - Household electrical appliances
      - Machines
      - Electrolysis
- - - - What is it?
        
        To provide a path for electricity to flow
      - Example
        
        Copper wire
    - - What is it?
        
        To convert electrical energy into other forms of energy to perform work
      - Example
        
        Electrical Appliances
        
        Lamps
        
        Fans
        
        Ovens
    - - What is it?
        
        To produce electricity
      - Example
        
        Battery
    - - What is it?
        
        To continue or discontinue the flow of electricity
      - Examples
        
        Switches
        
        Relays
    - - What is it?
        
        To stop the flow of electricity when it becomes dangerous
      - Examples
        
        Fuses
        
        Circuit breakers
  - - - Also called an incomplete circuit
      - Switch is open
        
        Break in the circuit (or path)
      - No electricity flows in the circuit
      - Other Causes
        
        Faulty working devices
        
        A break in the protective devices
      - Light bulb will not light up
    - - Also called a complete circuit
      - Switch is closed
        
        Circuit (or path) is complete
      - Electricity flows continuously in the circuit
      - Light bulb will light up
  - - - What is it?
        
        Materials that allow electricity to pass through them easily
      - Examples
        
        Silver
        
        Other metals
        
        Copper
      - Uses in electricity
        
        Copper is used as the conducting wire
    - - What is it?
        
        Materials that do not allow electricity to pass through them
      - Examples
        
        Plastic
        
        Rubber
        
        Glass
        
        Fibres
        
        Wood
      - Uses in electricity
        
        Plastic or rubber is used as protective layers on wires
    - - What is it?
        
        Materials that limit or regulate the amount of electricity passing through them
        
        Convert electrical energy into other forms of energy
      - Examples
        
        Nichrome
        
        Made up of
        
        Nickel
        
        Chromium
      - Uses in electricity
        
        Nichrome is used as the heating element to convert electrical energy into heat energy
- - - - Series Circuit
        
        The total voltage, V, supplied by the power source, is the sum of all the voltage in each electrical component
        
        V = V1 + V2 + V3 +...
      - Parallel Circuit
        
        The total voltage, V, supplied by the power source, is the same in each loop in the circuit
        
        V = V1 = V2 = V3 =...
    - - Definition
        
        Property of an electrical component that opposes the flow of electric charges through it
        
        A measure of how difficult it is for electric current to pass through an electrical component
      - Relationship between resistance, current and voltage
        
        Resistance (R) = Voltage (V)/Current (l)
      - SI Unit
        
        Ohm (Ω)
      - Resistance in a series circuit and a parallel circuit
        
        Series Circuit
        
        The total resistance, R, in a circuit is the sum of all the resistance in each electrical component
        
        R = R1 + R2 + R3 +...
        
        Parallel Circuit
        
        When the resistors are connected in parallel, the total resistance in the circuit is less than the resistance in each resistor
        
        1/R = 1/R1 + 1/R2 + 1/R3 + ...
      - Short Circuit
        
        A circuit without any loads
        
        Can be hazardous to the users
        
        Has the lowest resistance
        
        Electricity flowing in it can be too large
- - - - Rate of flow of electric charges
    - - Ampere (A)
      - A symbol of I
    - - Needed to move electric charges in a circuit
    - - In this mode, electric current flows from the positive terminal to the negative terminal of the power source in the circuit
  - - - Positive
      - Negative
    - - Energy supplied by the cells forces electrons to move out from the negative terminal of the source and flow in the circuit
      - Electrons flow back to the positive terminal of the source
      - Only energy of the source is used up eventually and not the electrons
      - The flow of electrons from the negative terminal to the positive terminal of a power source is called electron flow
  - - - The ammeter must be connected in series with other electrical components
      - The negative terminal of the ammeter is connected to the negative terminal of the power source
      - The positive terminal of the ammeter is connected to the positive terminal of the power source
    - - Series Circuit
        
        Electric current is the same at every point of each single loop regardless of the other components, whether they are identical or different
        
        l = l1 = l2 = l3 =...
      - Parallel Circuit
        
        Each loop has a different amount of electric current flowing in it
        
        The total current, I, in the electric circuit, is the sum of the current in all the loops
        
        I = l1 + l2 + l3 + ...
- - - - What is it?
        
        Has only one fixed resistance that cannot be changed
      - Uses
        
        Used mainly to reduce the amount of current and voltages in electrical components
    - - What is it?
        
        Resistance that can be changed to give a wide range of resistance
      - Uses
        
        To control the volume of a radio
        
        To control the speed of a fan
        
        To regulate the temperature of an electric iron
- - - - Electrical energy can be converted into heat energy
      - Resistance in electrical components resist the flow of electric charges
        
        Hence, electrical energy is converted into heat energy when it passes through the components
      - The greater the resistance a material has, the greater the amount of heat energy is produced
    - - Nichrome
        
        Resistance
        
        High
        
        Function
        
        Used to make the heating element in electric appliances such as electric kettle, oven, and toaster
      - Tungsten
        
        Resistance
        
        High
        
        Function
        
        Used as a filament in a light bulb to convert electrical energy into light and heat when it becomes very hot
      - Copper
        
        Resistance
        
        Low
        
        Function
        
        Used as a conducting wire to allow electricity to pass through easily
  - - - Electrical energy can produce a magnetic effect
      - When an iron bar is brought near or wound around by conducting wires. electric current flowing in the wires will induce them to be a temporary magnet
        
        This type of magnet is called an electromagnet
    - - Electromagnets lose their magnetism when the electric current stops flowing
      - The strength of an electromagnet can be increased by the following ways
        
        Increase the number of turns of wire in the coil
        
        Increase the amount of current in the coil
        
        Winding the coil around an iron core
      - Electromagnets are widely used in door bells, telephones and magnetic cranes that separate iron and steel from other materials in scrap yards
      - How an electromagnet in a doorbell works
        
        In a circuit of a door bell system, an iron core is wound around by conducting wires
        
        When electricity is turned on, the iron core becomes an electromagnet.
        
        It loses its magnetism when electricity is turned off
        
        When a person presses the door bell button at X, the switch is closed and the circuit is complete
        
        Electricity flows in the conducting wires and induces the iron core to be an electromagnet
        
        The electromagnet then attracts the hammer
        
        When the hammer moves towards the electromagnet, it hits the bell and the sound of the door bell is produced
        
        At the same time, the movement of the hammer makes a gap with the contact point
        
        This results in an open circuit in the system, so electricity is cut off
        
        The electromagnet loses its magnetism and no longer attracts the hammer
        
        The hammer returns to its original position
        
        The cycle repeats if the person continues to press the door bell button
        
        The sound of the doorbell will be produced at regular intervals
  - - - Electric current can produce a chemical change called electrolysis
    - - A chemical method used to break down a compound into its respective elements
      - Example
        
        Water (a compound) is broken down into hydrogen and oxygen (elements) when electricity passes through it
      - Terms
        
        Electrode
        
        An electrical contact that allows electric current to flow continuously between the electrolyte and the conducting wire
        
        Electrolyte
        
        A liquid or a solution that is able to conduct electricity
      - Applications of Electrolysis
        
        Electroplating
        
        The process of coating an object with a layer of metals
        
        The object to be coated with a layer of metal is to be placed at the negative terminal of the power supply
        
        The metal which coats the other object is placed at the positive terminal of the power supply
        
        Reasons why it is carried out
        
        To prevent objects made of iron and steel from rusting
        
        To enhance the appearance of an object such as making it more shiny
        
        Extracting pure metal from impurities
        
        Pure samples can be extracted from their impurities using electrolysis
        
        A sample of pure metal is placed at the negative terminal of the power supply
        
        The sample of impure metal is placed at the positive terminal of the power supply
        
        The metal from the impure sample will be separated from the impurities and coated onto the pure sample of the metal
- - - - One after one in a single loop or branch
    - - Only one
    - - Simple to build
    - - When more loads are added, the total resistance in the circuit increases
      - When one load is damaged, it affects the functionality of the other loads
    - - When one load is faulty, it causes a break in the circuit
        
        Circuit becomes an open circuit
        
        Electricity cannot pass through it anymore
  - - - Multiple loops or branches
    - - More than one
    - - When more loops are added, the total resistance in the circuit decreases
      - When one load is damaged, it does not affect the functionality of the other loads
    - - When one load becomes faulty, it causes a break in its own path only
        
        The rest of the circuits remain as closed circuits
        
        Electricity flows through them continuously