For my lab work, I have to design a method to measure the quality factor of an ideal inductor between 1MHz to 5MHz, away from resonance frequency. We know that an ideal inductor has the form (with a series resistor):
simulate this circuit – Schematic created using CircuitLab
The quality factor is defined as Q = wL/R, but the challenging part is we cannot take measurements between L1 and R1, since it isn't existed in real, I can measure only from node A and node B? I am allowed to use standard values of capacitors and resistors with a digital oscilloscope. Any ideas?
Best Answer
After the lab, I have come up with a solution:
As we have an inductor, we have two unknown variables: internal resistance and the inductance.
So, if we connect a series resistor and apply a sinusoidal wave then take a measurement between the inductor and resistor, we will observe and particular output voltage, and also an equation.
Then if we change the resistor value, again we obtain a different voltage value and equation. Since we have two unknowns and two linearly independent equations, we can find L and R by the help of linear algebra.