Signstek MESR-100 V2 Auto Ranging in Circuit ESR LCR Meter Capacitor/Low Ohm Meter Up to 0.01 to 100R, Support in Circuit Testing

What Makes It So Useful (For Real Work) The biggest win for me is in-circuit ESR testing. I don’t have to desolder every capacitor just to check if it’s bad. I can probe directly on the board and get a solid answer in seconds. That alone saves a ton of time. It uses a ~100kHz test signal, which is important because it matches how capacitor ESR is actually measured in real applications . Why I Trust It More Than a Multimeter A regular multimeter might tell me capacitance—but that doesn’t tell the full story. This meter shows ESR (internal resistance), which is usually what actually fails in caps over time. Low ESR → good cap High ESR → bad cap (even if capacitance looks fine) That’s huge when troubleshooting unstable power supplies. Where It Helped Me Most I’ve used it for: Xbox PSU repairs (huge here) Motherboards and GPUs Old TVs / monitors Random SMPS boards It’s especially useful when I’m chasing intermittent issues or unstable voltage rails. Fast, Simple, and Repeatable No menus, no complicated setup: Touch probes → instant reading Auto-ranging handles everything Built-in ESR chart helps quick comparison It measures roughly 0.01–100Ω, which covers most real-world capacitor failures

Love this thing, but the leads slip around when trying to clamp them and they are very short they should be longer and have the ability to put tiny probes on as well!!

This device has truly simplified the task of testing capacitors that are part of a circuit. It's the go-to solution if you don't want to go through the hassle of desoldering components just to perform a basic capacitor check. The auto-ranging feature is a lifesaver, making it incredibly easy to measure the Equivalent Series Resistance (ESR) and inductance (LCR) of capacitors while they're still soldered in. This is a game-changer for troubleshooting circuits and identifying faulty capacitors quickly and efficiently. Gone are the days of traditional, time-consuming desoldering and testing methods. The Signstek offers precision and convenience in one package, making it an invaluable tool for electronics enthusiasts and professionals. It has truly revolutionized the way we diagnose and maintain circuits, sparing us from the painstaking desoldering process. If you work with electronics and need to test capacitors in-circuit, this meter is a game-changer.

Works well to identify defective capacitors. As many people have said, the leads are not just too short, they are tied to close to one another. The leads need another 4" and the separation needs to be another 2" to be able to get to awkward connections.

I do electronics repair as a second job. This is a great tool for troubleshooting and saves me a lot of time. Bad capacitors are a frequent problem but they are difficult to test and I don't have the time to just replace every capacitor I run across on finicky equipment. PROs: Tests capacitors better than a multimeter without having to desolder them. Posts the results in plain English as well as the numeric readings. It's reliable. I have tested quite a few capacitors so far and the results so far are accurate and repeatable. It's inexpensive. I shopped around for a quality ESR and found that units typically cost more than this, have to ship from China or Russia, and frequently don't have as many features. CONSs: The battery door is difficult to get to. The stand is in the way. It's a minor hassle. I plan to just remove the stand entirely as I do not use it. It's not extremely precise, particularly on small capacitors. Caps below a certain point you have to look up on a table (which is handily printed on the unit). The numbers can vary a little but not enough to make a difference for what I'm testing. All I want to know is the answer to one question: "Is this a good cap?" It's precise enough to be accurate in answering this question and that is all I care about.