BK Precision - How to Use an LCR Meter

Our thanks to BK Precision for allowing us to reprint the following article.

Most LCR meters use AC signals to measure the impedance of components. Using an LCR meter is usually simple-but there are some setting choices you need to be aware of that will affect your measurements. In some cases, choosing the wrong settings can result in poor measurement accuracy. This article will give guidelines for picking the right settings for measurement frequency, measurement level, and equivalent circuit choice, along with some measurement tips.

Measurement frequency: Since the reactance is a function of frequency, your choice of measurement frequency should reflect the usage of the component. For capacitors, larger values (tens to hundreds of µF or more) are often used in power supply filtering applications, so should be tested at twice the line frequency. Smaller capacitors (fractions of a µF) tend to be used at higher frequencies, so should be tested at 1 kHz or more. A similar consideration applies for inductors. Smaller inductors (below 1 mH or so) should be measured at 1 kHz or higher, as they are often used in audio frequency or RF applications. Larger inductors are typically used as chokes and can be measured near line frequency.

Measurement level: Again, let the application of the component reflect your test conditions -- the measured value may depend on the voltage level across the component...

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