Siborg Systems Introduces Proprietary Calibration Boards to Extend Tweezer LCR-Meter Measurement Range Below 1 pF/10 nH

WATERLOO, ON, Feb. 18, 2025 /PRNewswire/ -- Tweezer-style LCR meters have gained significant popularity in recent years. However, a common limitation among all models is the presence of parasitic inductance and capacitance in the unshielded test leads, restricting the accurate measurement of very small inductances and capacitances. These parasitic effects vary with the distance between the test leads, depending on the component size.

To address this issue, Siborg Systems (Canada) offers proprietary calibration fixtures that effectively compensate for these parasitics, significantly improving measurement accuracy and range.

Since the introduction of the original Smart Tweezers LCR meter in 2005, numerous successors have entered the market. Some of these newer models surpass the original with higher test frequencies, improved accuracy, and additional functionality. Notably, the LCR-Reader line, including the MPA, R2, and R3 models, has expanded the capabilities of tweezer-based multimeters.

Despite these advancements, most tweezer meters share a similar structural design and continue to face the same limitations when measuring extremely small capacitances and inductances due to the parasitic effects of their test leads, as illustrated in the figure below.

The necessity of properly calibrating two-wire measurement setups was recently emphasized by Siborg Systems in IEEE publications, including AutoTestCon 2022 and the IEEE Instrumentation & Measurement Magazine (August 2023). These publications highlighted the critical role of calibration in accurately measuring small inductances and capacitances. Using an HP benchtop LCR meter, it was demonstrated that for inductances below 10 nH, the relative measurement error could exceed 100% if proper calibration was not applied.

This issue is even more pronounced in tweezer-style LCR meters, as demonstrated by Siborg in recent presentations at Nepcon Tokyo (January 2024) and the SMTA International Conference in Minneapolis (October 2024). At the latter event, it was shown that performing a proper short and open calibration using the proposed calibration fixtures (illustrated above) virtually eliminates parasitic offsets, enabling accurate measurement of capacitance and inductance below 1 pF and 10 nH, respectively.

Further details and publications are available at LCR-Reader website.

Capacitance and inductance offset values for the LCR-Reader MPA, R2, and R3 models vary depending on the component size from 0.014 to 0.249 pF and from 2.8 to 18.6 nH respectively. These offsets are common among all tweezer-style LCR meters and are typically not accounted for, leading to significant measurement inaccuracies. Obviously, without proper offset adjustments, parasitic effects can strongly impact measurement results.

To eliminate measurement offsets, Siborg Systems has introduced proprietary Short and Open Calibration Boards (patent pending), as shown in the image above. When these boards are used, measurement offsets are significantly reduced—to below 0.01 pF for capacitance and 1 nH for inductance.

The Offset Calibration Boards are specialized dummy PCBs with holes positioned at various distances to represent different component sizes (e.g., 0201, 0402, etc.). When a tweezer-meter's test leads are placed in the corresponding holes for a given component size, the device displays the actual offset capacitance. This offset value should then be subtracted from the measured component value for higher accuracy.

For LCR-Reader models (such as product of the year 2020 LCR-Reader MPA, R2, and R3), performing Open/Short calibration is simple:

When the device is connected to the Open/Short Calibration Board, pressing the joystick to the right until two beeps initiates calibration.
However, calibration accuracy can be affected by the pressure applied to the tweezer handles, which may cause variations of up to 0.005 pF and 0.5 nH. Maintaining consistent pressure during both calibration and measurement ensures better accuracy.

Since launching the Smart Tweezers LCR-meter project in 2005, Siborg Systems has been serving the electronics industry with continuous innovations. In recent years, advancements in accuracy (0.1%), test frequency (up to 250 kHz), and measurement range (0.1 pF to 1 F) have solidified the LCR-Reader product line as a market leader in precision electronic measurements.

Measuring extremely small capacitance and inductance values (below 1 pF and 10 nH)—which typically requires expensive benchtop meters—can now be done in under a minute using LCR-Reader MPA, R2, or R3 models, at a fraction of the cost.

Media Contact:
Michael Obrecht
519-888-9906
[email protected]

SOURCE Siborg Systems Inc