Ea-6 The Current Balance (Including the Kelvin Balance)


To demonstrate the current balance; a device for the absolute measurement of current.


  • Current balance as in diagram
  • D.C. Powerpak
  • Kelvin deci-ampere balance
  • Set of weights

The Current Balance

Kelvin Current Balance


The apparatus consists of a balance with a fixed coil B and a coil C suspended from one arm of the balance. The current to be measured passes through the coils such that the force is attractive. Balance is restored by the addition of weights to the pan on the other arm.

A Kelvin deci-ampere balance for measurements in the range 1/10 - 1 Ampere is also available.