Measurement Accuracy
The following points should be noted in order to achieve high accuracy in LCR measurements:
- High-precision reference resistor should be used.
- Use a sound card with low output impedance.
- Set measurement range correctly. Change the reference resistor value or the test frequency will change the range of measurement. The highest measurement accuracy is expected if the peak level in Step 2 is half of that in Step 1 and the peak level in Step 1 is close to 100%. This is similar to the case of measuring a resistor using an analog multimeter whereby the middle of the needle swing range has the highest measurement accuracy.
On the other hand, the frequency response of the sound card does not affect the accuracy in LCR measurements. Also, calibration of the sound card input and output channels is not required here.
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