MESR-100 ESR Capacitor Ohm Meter – In-Circuit Tester
MESR-100 ESR Capacitor Ohm Meter – In-Circuit Tester
MESR-100 Professional ESR & Low-Ohm Capacitor Tester
The MESR-100 ESR Capacitance Ohm Meter is a professional-grade tool designed for electronics technicians, hobbyists, and repair specialists. It measures the Equivalent Series Resistance (ESR) of capacitors with precision, using a true 100 kHz sine wave — the same measurement method used by capacitor manufacturers — so you get reliable, accurate readings every time.
Whether you're servicing a TV, LCD monitor, audio board, or any other electronic device, this meter lets you quickly determine if a capacitor is in good condition or has degraded — without removing it from the circuit.
Why Use an ESR Meter?
A capacitor's ESR (internal series resistance) rises as it ages or fails. A standard capacitance meter won't catch this — but the MESR-100 will. By applying less than 15mV DC peak-to-peak, it safely tests capacitors while they remain installed on the board, saving you hours of desoldering work.
Key Features
- Auto-Ranging: Measures ESR from 0.001Ω to 100.0Ω automatically
- 100 kHz Sine Wave Measurement: Cancels capacitive impedance for a true series resistance reading
- In-Circuit Testing: Apply directly on-board — no need to desolder components
- High Resolution: 4-digit display with 0.001Ω resolution in the 1Ω range
- Accuracy: Up to ±1% (range-dependent)
- Dual-Mode Operation: Auto mode (0–2s per reading) or Manual mode (~0.4s per reading)
- Dual Power Options: 2 × AA batteries (not included) or 5V Micro-USB external power
- Battery Life: Over 80 hours on AA batteries
- Printed Reference Table: Quick-check table printed on the unit for fast diagnosis
- Compact & Lightweight: 14.5 × 8 × 3 cm, 139.6g — easy to handle on the workbench
Measurement Range & Accuracy
| Range | Accuracy | Refresh Time (Manual) |
|---|---|---|
| 0.000 – 1.000Ω | ±1% + 2 Digits | ~0.4s |
| 1.000 – 10.00Ω | ±1% + 1 Digit | ~0.4s |
| 10.00 – 100.0Ω | ±2% + 1 Digit | ~0.4s |
Technical Specifications
- Color: Black
- Measurement Range: 0.001Ω – 100.0Ω ESR; works with capacitors >1µF
- Measuring Voltage: <15mV DC peak-to-peak
- Power: 2 × AA 1.5V batteries (not included) or 5V Micro-USB
- Operating Current: 0.02A
- Item Size: 14.5 × 8 × 3 cm (5.7 × 3.1 × 1.2 in)
- Item Weight: ~139.6g (4.9 oz)
- Package Size: 17 × 9 × 5 cm (6.7 × 3.5 × 2.0 in)
- Package Weight: ~218g (7.7 oz)
- Made in Mainland China
What's in the Box
- 1 × MESR-100 Capacitance ESR Meter
- 2 × Test Clips
- 1 × User Manual
Note: This meter measures the internal series resistance (ESR) of capacitors. It is not intended for measuring capacitance values.
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Frequently Asked Questions
Q: What does the MESR-100 ESR meter actually measure?
A: The MESR-100 measures the Equivalent Series Resistance (ESR) — the internal resistance — of a capacitor. It does NOT measure capacitance values. ESR testing is the most reliable way to identify aged, degraded, or failed capacitors, especially in TV, LCD, and audio board repairs.
Q: Can I test capacitors while they are still on the circuit board?
A: Yes! That's one of the MESR-100's standout advantages. It applies less than 15mV DC peak-to-peak during measurement, which is low enough that it won't affect or damage other components on the board, allowing safe in-circuit testing without desoldering.
Q: What power source does the MESR-100 use?
A: It can be powered by 2 × AA 1.5V batteries (not included), which provide over 80 hours of battery life, or by a 5V Micro-USB external power source for bench use — giving you flexibility in the field or at your workstation.
Q: What size capacitors can this meter test?
A: The MESR-100 is designed to work with capacitors greater than 1µF. It auto-ranges across a measurement span of 0.001Ω to 100.0Ω, making it suitable for a wide variety of electrolytic capacitors commonly found in consumer electronics.
Production & Packaging Notice
To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.