User Manual

18
above test frequency is used to measure capacitors that are 0.01 µF or
smaller. For capacitors that are 10 µF or larger, a frequency of 1 kHz or lower
can be used. Following this trend, high test frequencies are best for testing
very low capacitance components. For large capacitance components, low
frequency would be optimal. For example, if the capacitance of the
component is to be in the mF range, then selecting in the range of 20 Hz to
200 Hz for test frequency would give much better results. The results will also
be obvious because if the same component was tested with 1 kHz or above,
the measured readings may look erroneous on the display.
In all cases, it is best to check with the manufacturer’s data sheet in order to
determine the best test frequency to use for measurement.
Inductance
Typically, a 1 kHz test frequency is used to measure inductors that are used in
audio and RF circuits. This is because these components operate at higher
frequencies and require that they be measured at higher frequencies above 1
kHz. However, a 120 Hz test signal is used to measure inductors that are used
for applications such as filter chokes in power supplies, which are typically
operated at 60 Hz AC (in U.S.) with 120 Hz filter frequencies.
In general, inductors below 2 mH should be measured at 1 kHz frequency
while inductors above 200 H should be measured at 120 Hz.
In all cases, it is best to check with the manufacturer’s data sheet in order to
determine the best test frequency to use for measurement.
Choosing a Measurement Circuit Model
There are two measurement circuit models to choose from, series or parallel,
when characterizing components under test. The LCR meter will make
measurements regardless of which model is chosen, but components will
display more accurate results if the correct measurement model is selected.
To determine the better model to choose depends on the impedance of the
component at the specified frequency.