V = IR and Circuit Symbols

• What is the formula for potential difference?

  V = IR
• What does 'V' represent in the equation V = IR?

  Potential difference
• What does 'I' represent in the equation V = IR?

  Current (A)
• What does 'R' represent in the equation V = IR?

  Resistance (Ω)
• What are the circuit symbols for common components?

  • Battery
  • Switch open
  • Switch closed
  • Filament Lamp (or bulb)
  • Thermistor
  • Ammeter
  • Variable resistor
  • LDR (Light-Dependent Resistor)
  • Fuse
  • Voltmeter
  • Resistor
  • Diode
  • LED (Light-Emitting Diode)
• How are components connected in a circuit diagram?

  By straight lines representing wires
• What is the unit of potential difference?

  Volts (V)
• What is the unit of current?

  Amperes (A)
• What is the unit of resistance?

  Ohms (Ω)
• What does a thermistor do in a circuit?

  It changes resistance with temperature
• What is the function of an ammeter in a circuit?

  Measures current flow
• What is the purpose of a variable resistor?

  To adjust current flow in a circuit
• What does an LDR do in a circuit?

  Changes resistance based on light intensity
• What is the role of a fuse in a circuit?

  To protect against excessive current
• What does a voltmeter measure?

  Potential difference across components
• What is the function of a diode in a circuit?

  Allows current to flow in one direction