Electric curcuits cont.

    Cards (27)

    • The current is the same throughout all parts of the circuit.
    • Electric circuit
      A flow of charge
    • Electric current
      The rate of flow of charge
    • Cell or battery
      Produces an electric current by providing electrical potential energy to make charge move
    • Voltage or potential difference
      The ability of a cell to produce current
    • The circuit must be closed for charge to flow
    • Potential difference
      Measured using a voltmeter connected in parallel
    • Unit of potential difference
      Volt (V), one volt = one joule per coulomb (J•C-1)
    • Electric current is the rate of flow of charge, current needs a closed circuit, current flows everywhere in the circuit
    • Series circuit
      • Current is the same everywhere
    • Metals
      • Current consists of electrons that flow
    • Conventional current
      The flow of positive charge
    • Unit of current (I)
      Ampere (A)
    • Formula for current
      I = Q/Δt
    • Current measurement
      Using an ammeter connected in series
    • Electromotive force (emf)
      The maximum energy provided by a battery per coulomb of charge moving through it
    • Terminal potential difference
      The voltage measured across the terminals of the battery when current is flowing through the circuit
    • Load
      The combined effect of all the items such as light bulbs, resistors that cause charges to do work/transfer energy - known as total resistance
    • Conventional current is the flow of positive charge
    • The direction of current does not affect the size of current /voltage /readings in a circuit
    • Brightness of a bulb is a measure of current strength
    • Bulbs in series
      • Current is the same everywhere (identical bulbs are equally bright)
      • The higher the terminal voltage, the brighter the bulb
      • The greater the number of bulbs, the dimmer the bulbs
      • Voltage is split by bulbs in series
    • Bulbs in parallel
      • Current is split
      • Potential difference across each path is the same
      • Total current increases when bulbs are added in parallel
    • Resistance
      The property of a substance which hinders the flow of charge
    • Formula for resistance
      R = V/I
    • Factors affecting resistance
      • Type of material
      • Length - the longer the greater the resistance
      • Thickness - the thicker the less the resistance
      • Temperature - the hotter the greater the resistance
    • Definition of the unit of resistance, ohm
      If a potential difference of 1V produces a current of 1A then the resistance is 1Ω
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