In order to reduce the non-linearity of the core material, inductors are generally measured with a large internal resistance of 100 ohms to reduce the test signal level. In order to compare the data with other competitor testers, it must ensure that they have the same internal resistance. Other modes are available as impedance options as long as this is consistent with the manufacturer's specified internal resistance test conditions.

The quality factor Q of an inductor indicates the degree to which the device approaches a pure reactance. A higher Q value indicates a larger absolute value of reactance, a smaller series resistance, and lower energy loss.

For capacitors, the purity is usually represented by the dissipation factor D, where D = 1/Q. Therefore, a smaller D value corresponds to a larger capacitive reactance and better efficiency.