Inductors are ubiquitous, being indispensable in circuits such as loudspeaker crossover networks, switchmode power supplies and RF amplifiers. Unlike other components, inductors are often hand-made, particularly when prototyping or assembling a do-it-yourself project. At a minimum, this suggests the need for a meter to check inductance values prior to use in circuit.

But that is not the end of the story. Of all the passive components, inductors typically show the greatest deviation from ideal behaviour. This is due primarily to coil resistance and the hysteresis of the core material.

The picture is further complicated by the fact that the losses are frequency dependent. The skin effect in copper wire and the complicated frequency characteristics of magnetic materials both come into play and are apparent even at audio frequencies.

To provide a more informative picture of inductor performance then, this new meter allows you to measure the Q factor of a prospective resonant circuit at the operating frequency. If you’ve never heard of Q factor, then read on...

Specifications Range Inductance: 200nH - 10mH Q-Factor: 1-120 (approx.) Power Supply 9V DC 200mA plugpack Features (1) Internal or external tank capacitance facility for accurate Q measurements (2) Measurement frequency autoranging up to 20MHz