Topic Summaries

Key concepts of circuits

GCSE > Physics > OCR B > GCSE Physics Topic Summaries > Circuits > Key concepts of circuits
Previous Module
Next Module

Science skills: Measuring results

  • Current (I ) is the flow of electric charge, measured in amperes (A).
  • Voltage (potential difference, V ) is the energy transferred per unit charge, measured in volts (V).
  • Resistance (R ) opposes current flow and is measured in ohms (Ω).
  • Charge (Q ) is measured in Coulombs (C) and calculated as Q = I × t.
  • Circuits contain a variety of components:
    • Switch: a device used to open and close a circuit, allowing or stopping the flow of current. If the switch is open, the circuit is broken and current cannot flow.
    • Cell/battery: provides energy to push charge around the circuit.
    • Ammeter: measure the electric current flowing through a circuit, in amperes. It is always connected in series with the component being measured.
    • Voltmeter: measures potential difference (voltage) across two points in a circuit. It is always connected in parallel with the component being measured.
    • Resistor: limits the current in a circuit.
    • Variable resistor: allows current to be adjusted by changing resistance.
    • Fuse: a safety device containing a thin wire that melts and breaks the circuit if the current exceeds a certain limit, protecting components from damage or fire.
    • Lamp: produces light when current passes through it.
    • Diode: allows current to flow in one direction only.
    • LED: emits light when current flows through it in the correct direction.
    • Thermistor: resistance decreases as temperature increases (used in thermostats).
    • LDR (Light Dependent Resistor): resistance decreases as light intensity increases

Unlock Key concepts of circuits

Subscribe to SnapRevise+ to get immediate access to the rest of this resource.

Premium accounts get immediate access to this resource.

Previous Module
Next Module