Varmeter is used to indicate the amount of reactive change. In this type of varmeter the pressure is made highly inductive such that voltage across the pressure coil lead by the pressure coil current by angle of 90°. The coil current is the load current which has phase difference of ‘ϕ’. Reading of Varmeter = VI cos (90 – ϕ) = VI sin ϕ Which is mathematically equal to the reactive power of the circuit.