Measuring an Inductor with DC Bias

This video shows an example of using a line injector and oscilloscope to measure frequency dependent inductance with a 1 A DC Bias current applied to the inductor.

Power supplies include inductors both in the input and output filters.  The effective inductance of these components can be significantly reduced at high operating current, resulting in increased ripple and EMI.  Testing with a DC bias can help you understand an inductor’s in-circuit performance.

Source:

• Arbitrary/Function Generator (built into 6 Series MSO)
• Bench power supply
• Picotest J2121A High Power Line Injector

Measure:

• 6 Series MSO Oscilloscope

Videos recorded by:

Tony Ambrose, Application Engineer, Tektronix