Power Inductor Checker

There are three kind of passive electronic component, Inductor, Capacitor and Resistor. The inductor is an only component that can be built easy and many type of core and bobbin kits are available. When wind it yourself, an inductance meter is needed to measure if it is in desired specs or not. However measurement of inductance is relatively difficult because the inductance varies depends on measurement frequency and DC bias current. For tuning inductors in radio circuit, it should be measured at working frequency. And for choke inductors used in SMPS, variation of inductance by load current, especially point of core-saturation, must be known.

This project build an inductor measurement adapter specified for power inductors. Also an oscilloscple, 20MHz or higher, is needed for measurement.

Theory

When a constant DC voltage E is applied to an inductor Llike shown in right image, the current I increases proportional to the time past, I = E * t / L. If the inductance is constant independet of DC current, ploted line on the graph will be straight. However it is affected by DC current, it will plot a curved line.

Thus the inductance and its current-dependency can be easily measured by applying a voltage pulse to the inductor and displaying the current on the oscilloscope.

Hardware

For more information,pls contact us at sales@xfullstar.com