Consider the following Maxwell inductance bridge circuit used to characterize the inductance modeled as the self-inductance and its equivalent series resistance .

By properly adjusting the variable resistor  and the variable self-inductance , the bridge is kept in equilibrium at , i.e. .

Under these circumstances, .

As for the inductor , its equivalent series resistance is .

Estimate the ratio between the unloaded quality factors of the inductors and (without in ), i.e. .