How to Test a Capacitor with a Multimeter—Capacitance Isn’t Enough!

How can a capacitor measure the correct capacitance and still be bad? In this video, I demonstrate how to test a capacitor with a multimeter, measure ESR with an LCR meter, and perform a high-voltage leakage test. I begin with an old 40 µF, 450 V electrolytic capacitor. It measures approximately 41 µF on the FNIRSI DST-201 and about 38 µF with 2.2 ohms ESR on the FNIRSI LC1020E. Those readings might make the capacitor appear usable—but its behavior changes dramatically when actual operating voltage is applied. FNIRSI test equipment shown in this video: FNIRSI 2C53T https://amzn.to/4ylxo7Z FNIRSI DPOS350P https://amzn.to/4iyG3PZ FNIRSI DST-201 https://amzn.to/4xbvbuK FNIRSI LC1020E https://amzn.to/4r63n9W As an Amazon Associate, I earn from qualifying purchases. Using these links may earn the channel a small commission at no additional cost to you. ⚠️ HIGH-VOLTAGE SAFETY WARNING This video contains potentially lethal voltages. High-voltage capacitors can retain a dangerous charge after power has been disconnected and may regain some voltage through dielectric absorption. Do not attempt these tests unless you understand high-voltage safety procedures and have the appropriate equipment and experience. Always use suitable current-limiting and discharge resistors. Switch off and disconnect the power before making circuit changes. Discharge every capacitor safely and verify zero voltage with a properly rated meter before touching it. Never leave a capacitor unattended during a high-voltage test. Old or defective capacitors may overheat, vent or rupture. This video is for educational and informational purposes. You are responsible for your own safety and equipment. If you enjoy practical electronics testing, vintage equipment restoration and real-world bench experiments, please subscribe to OhmWorksLab and let me know in the comments what capacitor test you use most often. @ohmworkslab #CapacitorTesting #ElectronicsRepair #ESRMeter #highvoltage #Capacitorleakage #fnirsi #lcrmeter 00:00 Intro to how to check a capacitor 01:17 High Voltage setup 01:57 Testing Capacitors 04:28 Death Cap 06:00 Bumble Bee Cap 06:47 FNIRSI Meters 07:00 Cheap vs Name Brand Capacitors 09:57 Ripple Test FNIRIS DPOS350P 12:17 Conclusion