Current, Potential difference and Resistance

The electric current in a circuit is determined by:

  • The potential difference (often referred to as voltage) from the power supply.
  • The resistance of the components in the circuit

Electrical work is done when an electric current flows through a circuit. We can calculate the current, potential difference or resistance using the equation:

PERSONALISED 1-TO-1 TUTORING

Need more help on this topic? Get 1-to-1 support

Get support with clear explanations, practice and feedback (Ages 5 to 16).

  • DBS-checked tutors
  • Flexible times
  • Parents can be updated

Want an ad-free experience? Subscribe to remove ads

  • V = Potential difference in volts (V)
  • I = Current in amperes (A)
  • R = Resistance in ohms (Ω)

It is not possible to directly change the electric current in a circuit, as the current is dependent on the potential difference and resistance.

Resistance

Resistance is a measure of the opposition to the flow of current, which is measured in ohms (Ω). As you increase the resistance, it becomes more difficult for the current to flow through.

  • Conductors have a low resistance
  • Insulators have a high resistance

Ohm’s law states that the current is directly proportional to the potential difference, provided the temperature remains constant.

You’ve used 10 of your 10 free revision notes for the month

Sign up to get unlimited access to revision notes, quizzes, audio lessons and more

Sign up