Measurements

D.C. & A.C.

  • D.C. voltages and currents may be measured using digital or analogue meters
  • The commonly used analogue meter movement is the moving coil meter – a small current in the coil sets up a magnetic field that causes the meter to rotate;  the rotation is opposed by the spring, so that deflection is proportional to the average value of the current
  • The sensitivity of the meter is defined by the current flow for full scale deflection (fsd)
  • Moving coil meters start at about 50μA fsd