Using External DC Bias Current Sources with LCR Meters R&S®LCX

Ideal inductors are assumed to have linear behavior, i.e. their properties should not depend on signal amplitudes or superimposed DC bias current. Real inductors often contain magnetic core material, in order to achieve higher inductance within an available volume. All magnetic core materials exhibit nonlinear behavior in the shape of hysteresis and saturation effects. Testing the properties of an inductor depending on test signal amplitude and DC bias current is therefore indispensable for the component characterization.

With option R&S®LCX-K108, LCR meters R&S®LCX100 and R&S®LCX200 can superimpose DC bias current up to 200 mA. For higher DC bias currents, an external source is required. This external source can be connected in parallel if it has a sufficiently high impedance over the measurement frequency range.

This application note explains how to connect an external DC bias current source, avoid risks and hazards, and perform corrections for optimum measurement accuracy.