Why I Switched to Real Murata Parts (and How to Test Capacitors with a Multimeter)

It was a Monday in February 2024 when the data logger in our production bay died. The screen still lit up, but the readings were stuck at 42.3°F. The internal engineer said the most likely cause was a failed capacitor. “Check the board,” he said. “Most of the small parts are Murata. Look up Murata Electronics — we need Murata resistors and capacitors.” I didn't understand half of it. I was the office administrator, not an engineer. My job was managing vendors and making sure invoices didn't get rejected.

So I did what any purchaser would do. I searched for “murata resistors,” compared a few suppliers, and picked a listing that looked reliable. Not the cheapest, but not the most expensive either. I hit “order” and felt good about saving the company a few dollars. That feeling didn't last.

The First Lesson: Testing Capacitors with a Multimeter

The package arrived in two days. The engineer didn't solder anything. Instead, he pulled out a multimeter and began testing each capacitor before installation. I watched the display bounce around: 44 nF, 50 nF, 38 nF. The label on the parts said 100 nF. He looked at me. “These are nowhere near spec.”

We tested more. Every one was below tolerance. One or two were so far off they would have caused the exact kind of signal noise we were trying to fix. The parts looked perfectly fine. No burns, no cracks, no bulges. They just didn't hold their rated capacitance.

That was my first real lesson in testing components. Here's the thing: a multimeter can tell you whether a capacitor is in the right ballpark, but only if you use it properly.

How to test a capacitor with a multimeter

1. Discharge the capacitor first. For large electrolytics, use a resistor or the meter's own discharge function. For small ceramics, just make sure the board is off.
2. Switch the multimeter to capacitance mode. It's usually marked with a symbol that looks like two parallel lines.
3. Insert the probes firmly. A loose jack connection will give you erratic readings.
4. Wait for the reading to stabilize. Large values can take several seconds.
5. Compare the reading to the datasheet value and its tolerance. A 100 nF capacitor rated ±10% should read between 90 and 110 nF.

My own cheap “Infinity Pro” multimeter didn't help. The input jacks were loose, so probe resistance varied and readings wandered. I blamed the parts at first, but the real problem was my test equipment. Once I borrowed a better meter with clean, snug jacks, the numbers settled down. That's a practical reminder: before you condemn an electronic component, make sure your multimeter is actually trustworthy.

The Hidden Problem: ESR and the Limits of a Simple Test

A capacitance reading is only part of the story. Capacitors also have ESR — equivalent series resistance. If ESR is too high, the part can overheat in power circuits and fail even when the capacitance looks normal. A basic multimeter won't show you ESR. My cheap meter certainly didn't.

I don't have hard data on how many failures come from high ESR versus low capacitance. But after watching that engineer work through the board, my sense is that ESR is often the quiet culprit in power supply and filtering circuits. If you're troubleshooting something like a DC-DC converter or an audio amplifier, invest in a component tester or an ESR meter. The extra cost is tiny compared to a second round of debugging.

The Real Cost of a Cheap Capacitor

We threw out the whole batch of cheap capacitors and reordered from an authorized distributor. This time, I checked the markings against the Murata datasheet. I also verified the series page on Murata's website — accessed March 2025 — to confirm the capacitance tolerance and voltage rating. The genuine Murata parts measured within spec. The device worked on the first try.

Now let's talk about total cost of ownership.

The cheap capacitors cost about $0.75 each. The genuine Murata capacitors cost roughly $1.10 each. On a 25-piece order, that's a difference of less than nine dollars. But the cheap parts caused:

Hours of engineering time, a failed repair attempt, extra shipping for the correct parts, and a compliance data gap that made our operations manager nervous. By the time we were done, that “savings” had easily turned into $1,500 or more in lost time and rushed freight. The more expensive part was actually the cheaper purchase. Pretending otherwise just costs more.

Same logic applies to other Murata components. We had a wireless sensor tag with a Murata micro battery that held data and kept the radio alive during brief power blips. The replacement battery looked expensive compared to a standard coin cell. But the alternative was regular maintenance visits and data loss. In that context, the Murata micro battery was the low-TCO option, even if the upfront price was higher.

What I'd Tell Another Office Manager

You don't need an engineering degree to make good component purchases. You need patience and a simple checklist.

First, buy genuine parts from reputable distributors, especially when the original design uses a well-known brand like Murata Electronics. Generic replacements can look identical and fail quietly. Second, test critical components before installation. Learning how to test a capacitor with a multimeter took me twenty minutes, and it saved us from a much bigger headache. Third, keep your test gear in good condition. If your meter's jacks are loose or probes are damaged, replace them. Finally, track the total cost of every purchase, not just the price tag. The cheapest quote is often the most expensive thing you can buy.

I still look for deals. That won't change. But now I weigh reliability, traceability, and downtime against the little line item called unit price. That shift in thinking turned one failed capacitor order into a genuinely better purchasing process.