Many of these newer LCR Meters, Tweezers, Handhelds or Bench types, employ the Auto-Balance LCR Architecture where the DUT voltage and current are measured and the DUT complex impedance computed from such.
This architecture uses a scaled Transimpedance Amp to measure the DUT Current in a "Virtual Ground" configuration in which DUT current is supplied by the meter source thru a controlled source resistance. The meter must supply the source DUT current as well as sink this current thru the Transimpedance amp, which places demands on the meter circuitry to handle these high currents at higher frequencies for low Z DUT devices.
Low DUT Z requires significant DUT current to produce an acceptable DUT voltage for measurement. If one considers DUT Capacitive Impedance @ 100KHz, this equates to ~1.6uΩ/Farad DUT Z. So a 160uF Cap only has ~10mΩ impedance and with a high test source current of 100ma only produces 1mv DUT voltage. Here a 1KHz measurement makes more sense as the resultant DUT voltage now becomes 100mv and much easier to accurately resolve. Conversely an inductance follows the opposite, for example a 1.6uH inductance has an impedance at 1KHz of 10mΩ and the measurement would benefit from using 100KHz as the impedance increases to 1000mΩ.
Consider having an LCR meter capable of delivering higher source (and sink) currents at higher (and lower) frequencies if Low Z DUTs are involved, and comes as no surprise that Tweezers, Handhelds and lower cost Bench Meters where battery and or cost become major factors, have limited frequency and DUT impedance ranges.
Anyway, hopefully this illustrates the importance of knowing how these meters operate, the limitations, and how the DUT characteristics must be considered when making quality measurements.
In all cases KTI (Know Thy Instrument) is a requirement for better measurements
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