What Is an LCR Meter?

LCR stands for:

An LCR meter applies an AC test signal to a component and measures the resulting voltage, current and phase relationship. From this information it can calculate parameters such as resistance, capacitance, inductance and impedance. Depending on the instrument, it may also display ESR, dissipation factor (D), quality factor (Q) and other component characteristics.

This makes LCR meters useful for electronics repair, PCB diagnostics, component sorting, prototyping, laboratory work, capacitor testing and inductor analysis.

You can browse the ZOYI UK LCR Meter range for dedicated component-testing instruments.

LCR Meter vs Digital Multimeter

A digital multimeter is primarily a general electrical diagnostic instrument. An LCR meter is primarily a component-analysis instrument. The two tools therefore complement one another rather than directly replacing each other.

For voltage, current, continuity and general electrical diagnostics, see the ZOYI Digital Multimeters UK range.

How to Test a Capacitor and ESR with an LCR Meter

For the most meaningful capacitance measurement, disconnect power, safely discharge the capacitor and isolate it from the surrounding circuit where practical. Connect it to the LCR meter, select capacitance mode or automatic L/C/R detection, choose a suitable test frequency and wait for the measurement to stabilise.

What Is ESR?

ESR means Equivalent Series Resistance. A real capacitor has internal losses, and ESR is one useful way of representing part of those losses as resistance.

ESR can be useful when troubleshooting electrolytic capacitors in power supplies, audio equipment, control boards and other electronics. However, there is no universal ESR value that defines every capacitor as good or bad. Expected ESR depends on capacitance, voltage rating, component construction, temperature, frequency and product series.

What Test Frequency Should You Use?

Test frequency is one of the most important settings on an LCR meter because capacitors and inductors are frequency-dependent devices. A component may legitimately produce different readings at 100 Hz, 1 kHz, 10 kHz and 100 kHz.

The ZOYI ZT-DQ01 LCR Meter provides selectable 100 Hz, 1 kHz, 10 kHz and 100 kHz test frequencies together with selectable test-signal levels.

For a deeper technical explanation of LCR measurement and frequency-dependent behaviour, see Hioki's technical guide to LCR meter measurement.

Series vs Parallel Measurement Mode

An LCR meter calculates component values using an equivalent electrical model. In series mode, the reactive component and its resistance are modelled in series. In parallel mode, the resistance is modelled in parallel with the reactive component.

Hioki notes that series mode is generally appropriate for relatively low-impedance components, while parallel mode is commonly used for high-impedance components. When the correct equivalent circuit is uncertain, the component manufacturer's measurement specification should take priority.

See the external reference: Hioki – Selecting the Equivalent Circuit Mode of an LCR Meter.

Can You Test Components In-Circuit?

Yes, an in-circuit reading can be useful for troubleshooting, but it must be interpreted carefully.

The meter may see not only the component under test but also other resistors, capacitors, inductors and semiconductor paths connected around it. As a result, the displayed value may differ considerably from the marked component value even when the component itself is healthy.

You can also read our existing beginner guide to testing capacitance, resistance and LCR components.

Why Use Kelvin Clips and 4-Wire Measurement?

When resistance becomes very small, ordinary probe and lead resistance can form a significant part of the measured value.

A Kelvin or four-terminal connection separates the current path from the voltage-sensing path. This reduces measurement error caused by test leads and contacts and becomes particularly useful for milliohm measurements, ESR, windings and battery internal resistance.

ZOYI also supplies 4-wire Kelvin test leads for compatible LCR and low-resistance measurements.

Why Calibration and Open/Short Compensation Matter

Test fixtures and leads have their own resistance, capacitance and inductance. These parasitic effects can significantly influence measurements of very small component values.

Open and short compensation allows supported LCR meters to characterise and compensate for some of those fixture effects. Repeat the procedure when required by the instrument, especially after changing test leads or fixtures.

Hioki also explains open and short correction as part of its LCR meter measurement guide.

LCR Tweezers for SMD Components

LCR tweezers make it much easier to grip small SMD resistors, capacitors and inductors directly between two test tips. They are particularly useful for PCB repair, component sorting, prototyping and identifying unmarked passive components.

Can an LCR Meter Test Battery Internal Resistance?

Not every LCR meter can safely be connected to a battery. A battery presents DC voltage at its terminals, and a conventional LCR meter may not be designed to tolerate that external voltage.

The ZOYI ZT-DQ02 is specifically designed for both LCR component testing and battery internal-resistance testing.

For more information about choosing specialist component testers, see our guide to LCR, ESR, SMD and battery internal-resistance testers.

Common LCR Meter Problems

Frequently Asked Questions

Technical note: Measurement methods, test frequencies, signal levels and available functions vary by instrument and component. Follow the relevant component datasheet, LCR meter manual and appropriate electrical safety procedures.