An LCR meter measures inductance, capacitance and resistance properly at a chosen test frequency and bias, in series or parallel model. Those settings explain why the same part reads differently on different instruments and on the component's datasheet.
At a glance: 6 minute guide · part 8 of 10 in the tools and equipment complete guide track · includes a worked example and a quick-reference table.
Frequency and bias matter
Capacitors and inductors are frequency-dependent: electrolytics measured at 100/120 Hz read their bulk value. Ceramics are characterised at 1 MHz. Choose the datasheet's test conditions when comparing, or accept the difference knowingly.
| Part | Test frequency | Model note |
|---|---|---|
| Electrolytic cap | 100/120 Hz | Series (Cs, D) |
| Ceramic cap | 1 kHz–1 MHz | Bias derating! |
| Film cap | 1 kHz | Either |
| Power inductor | 100 Hz–100 kHz | Series (Ls, DCR) |
| RF inductor | ≥ 1 MHz | Parallel (Lp, Q) |
Series or parallel model
What this means at the bench. The meter reports either a series (Ls, Cs, D) or parallel (Lp, Cp, Q) equivalent. For low-value caps and high-value inductors, series; the reverse for the reverse. At moderate values both agree the model choice matters at the extremes datasheets flag.
Practical craft
Zero the leads (open/short compensation), use the four-terminal kelvin clips for low impedances. Keep parts away from metal benches. Measure MLCCs at their working bias when DC bias derating matters a 10 µF ceramic can read 4 µF at voltage.
How to apply this in your build
Work through the sequence below each step assumes the previous one passed. For numbers that need calculating, the linked tools at the end of this guide do the arithmetic instantly.
- Run open and short compensation before measuring
- Select frequency matching the datasheet condition
- Choose the equivalent model per part type
- Bias ceramics near working voltage for truth
Worked example
A 10 µF MLCC on the bench reads 9. 6 µF and 4. 3 µF with 5 V bias applied. The regulator that “misbehaved” was designed around a fantasy capacitance. Run the numbers yourself with the Capacitor Code (3-Digit) and the result should agree to within rounding.
Practical note from the bench. Component verification at Procirel happens at datasheet conditions the same part, same frequency, same story every time.
Field mistakes we see again and again
- Comparing readings taken at different frequencies
- Trusting handheld “cap meters” on DC-biased ceramics
- Measuring inductors in-circuit through parallel paths
Key takeaways
- Frequency and bias matter the foundation of this guide; revisit it if any measurement here surprises you.
- Series or parallel model the foundation of this guide; revisit it if any measurement here surprises you.
- Practical craft the foundation of this guide; revisit it if any measurement here surprises you.
Prerequisites and preparation
Before starting: run open and short compensation before measuring and select frequency matching the datasheet condition. Keep the Capacitor Code (3-Digit) and Inductive Reactance open every number in the worked example is reproducible. Total time including the bench steps: about 6–6 minutes.
Who benefits most
Hobbyists meeting this topic for the first time, students who want the version with real numbers instead of abstract symbols. Returning engineers refreshing a corner of the craft. The mistake list alone justifies the visit every entry in it was learned the expensive way.
Quick reference card
| Aspect | Where to find it in this guide |
|---|---|
| Core theory | Frequency and bias matter |
| Application steps | How to apply this in your build |
| Worked numbers | Worked example |
| Failure modes | Field mistakes we see again and again |
How this fits the tools and equipment complete guide track
This guide is one stop in the structured learning path. Start from the tools and equipment complete guide complete guide for the full map, or continue with digital bus capture and probe calibration. For the arithmetic, open the Capacitor Code (3-Digit) or Inductive Reactance.
Frequently asked questions
Why the discrepancy with my multimeter’s cap mode? Multimeters use one fixed method/frequency convenient, not characterising. The LCR meter tells the whole truth.
When do I need kelvin clips? Below a few ohms or above a few henries, lead resistance and coupling dominate readings.
Is there a calculator for this? Yes the Capacitor Code (3-Digit) and Inductive Reactance tools run the formulas from this guide instantly, client-side, with no signup.
What to read after this
- The complete tools & equipment guide: Tools & Equipment complete guide
- Read next: how to use a multimeter: every mode that matters
- Also in this track: oscilloscope triggering: the skill that makes waveforms stand still
- Continue with: probe compensation: the one-minute scope calibration
- Calculate as you go: frequency and wavelength tool · trace width calculator · resistor decoder
- From here, the natural continuation is the next guide in the track index. It assumes exactly the vocabulary this page built and adds the next layer of practice.
Field notes
The fastest way to internalise this topic is to change one variable deliberately and predict the result before measuring. Wrong predictions are the curriculum, they show exactly which mental model needs revisiting, and the bench grades honestly.
Component substitution is a legitimate experiment as long as it is deliberate. Swap one part, predict the effect, measure, and record. That single habit converts a parts bin into a teaching lab and makes every future guide in this track faster to absorb.
Formulas and checks from this guide
Verification checklist for this track: compensate probes before trusting amplitudes, verify meter fuses before current work. Keep one known-good reference to sanity-check instruments. Calibration you can demonstrate beats calibration you assume.
Bookmark this page against your next build in the track. The checklist above is the same one used across 12 guides in this series.
Field lessons worth keeping
Warm-up drift is real in both. Swap in a known-good reference to decide which side drifts.
After every move between scopes, and monthly as ritual. It costs one minute.
The habit that makes this stick
A note on instrument trust, the habit of this track: compensate probes, verify meter fuses, keep one known-good reference. Calibration you can demonstrate beats calibration you assume.
Working through Frequency and bias matterand Series or parallel model with that habit in mind takes minutes, and it is the difference between reading about this topic and owning it.
Last updated 23 August 2026