All PSoC Application Notes

AN2053: LCR Meter

The LCR Meter measures the characteristics of a passive component. It has the following features: • Measures the capacitance, inductance, resistance, quality factor, dissipation factor and phase angle of a component’s impedance • Displays the real part (resistance), the imaginary part (capacitance or inductance) and one selectable third result at the same time • Resistance range: from 100.0mΩ (resolution 0.1mΩ) to 1.000MΩ • Capacitance range: from 100.0pF (resolution 0.1pF) to 10.00mF • Inductance range: from 10.00uH (resolution 10nH) to 10.00mH • Some results from non-exhaustive accuracy test: error of 0.07% at 10nF, 0.16% at 10kΩ, 2.4% at 100uH • Stimulus frequency ranges from 50Hz to 10kHz in 195 user-selectable, crystal-controlled discrete steps • Stimulus AC amplitude is selectable from three different values: 250mV, 500mV, 1V • Stimulus DC bias can be set internally to 2V or externally to any voltage up to 50V • The resistive and reactive parts of either a series or a parallel equivalent circuit can be displayed • Four-wire measurement interface compensates for test setup contact resistance • Two-wire measurement interface included additionally • Guarded measurement eliminates parasitic capacitances between measurement path and ground • Shielded cables between the LCR meter and the component under test can be used without disturbing the measurement, thus eliminating the parasitic capacitance between probe cables • Measured capacitance can be offset to 0 to compensate for additional parasitic capacitance in the test setup • Measurement terminals are protected against hard short-circuits to external voltage sources up to +/- 12V • Uses a large, low-cost LCD display for providing a maximum of information at the same time • Rotary encoder provides easy user interface • Small keyboard additionally provides fast access to three parameters • RS232 interface sends measurement results and can be used to set up measurement parameters • Accuracy mainly determined by only a few precision resistors, calibration only necessary for a secondary function