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electricity - Coggle Diagram

- - - - The resistance: If the resistance is increased, the current will decrease.
      - The potential difference: If the potential difference is increased the current will increase.
  - - - To measure the resistance of a component (e.g. lamp or resistor), measure the potential difference across the component.
    - - Use an ammeter to measure the current flowing through a component.
    - - The longer the wire, the higher the resistance
- - - - One coulomb of charge is a package equivalent to 6,250,000,000,000,000,000 electrons.
- - - - charge (Q) is measured in coulombs (C)
  - - - Potential difference (p.d.) is measured in volts (V) and is also called voltage.
      - The energy is transferred to the electrical components in a circuit when the charge carriers pass through them.
      - We use a voltmeter to measure potential difference (or voltage).
- - - - A switch used to turn a circuit on (closed) and off (open).
    - - An electrical current heats the filament in a bulb so that it gives out light.
    - - A resistor restricts or limits the flow of electrical current. A fixed resistor has a resistance that does not change.
    - - Moving the position of the slider on this resistor, changes the resistance. A variable resistor is used in some dimmer switches and volume controls.
    - - The resistance of a thermistor depends on its temperature. At low temperatures, the thermistor has a high resistance. As the temperature increases, the resistance decreases. A thermistor can be used in thermostats or heat activated fire alarms.
    - - The resistance of a LDR depends on light intensity. At low light levels, the LDR has a high resistance. As the light intensity increases, the resistance decreases. A LDR can be used as a sensor in cameras or automatic lights that come on when it gets dark.
    - - A semiconductor diode allows current to flow in one direction only. Current will not flow in the other direction. Diodes are used to convert an alternating current into a direct current.
- - - - charge (Q) is measured in coulombs (C)
        
        One amp is the current that flows when one coulomb of charge passes a point in a circuit in one second.
      - current (I) is measured in amps (A)
      - time (t) is measured in seconds (s)
- - - - An ammeter measures the flow of current that passes through it.
      - Ammeters have to be connected in series (in the same loop of the circuit) with the electrical component whose current you are measuring. For example component X above.
    - - Voltmeters measure the potential difference (voltage) between two points in a circuit. For example between two points either side of component X above.
      - Voltmeters must always be connected in parallel (on a separate branch of the circuit) with the two points being measured.
    - - The current is a flow of charge. Current is measured through a component.
      - Potential difference is the energy used between two points in a circuit, therefore it is measured between two points either side of a component.
      - We describe this as the potential difference measured across a component.