I'm a procurement manager at a medical device company, and I handle about $180,000 in annual component spend. When I first started managing component sourcing, I assumed the lowest quote was the best choice. Three budget overruns later, I finally understood what total cost of ownership actually means.
This is the story of how I learned that lesson. It involves a blood pressure monitor, a batch of tantalum capacitors, and a spreadsheet that changed how our company buys Kemet components.
It Started With a Spreadsheet
In Q2 2024, our design team asked me to source tantalum capacitors for a new blood pressure monitor. The engineering spec called for a 10 µF, 16 V tantalum capacitor in a 1206 package. The engineer had written Kemet T491 on the BOM, but honestly, I didn't care about the brand. I cared about price per part.
So I sent the spec to three distributors. The first quote, from our authorized Kemet distributor, came back at $0.42 per piece. The second, from a vendor we'd used for other passive components, came back at $0.31. The third was somewhere in between.
The numbers said go with the $0.31 option. My gut said something was off—that vendor's lead time was vague, and the datasheet they sent didn't look as polished. But I went with them anyway. That's the part I still kick myself about.
The 2,000-Part Problem
Two weeks later, 2,000 capacitors showed up. Our electrical engineer ran 20 boards through assembly. One failed. Then another. We pulled out the multimeter and started testing.
If you're doing any kind of electronics work, this is where the right tool matters. The best multimeter for electronics isn't the most expensive one—it's the one with accurate capacitance and ESR measurement. Our old meter didn't have that. So we bought a new one (around $150, give or take) and tested a sample of the parts.
Basically, the results weren't pretty:
- About 5% of the parts measured 8.2 µF instead of the specified 10 µF.
- ESR was higher than the spec allowed on some parts.
- The vendor's “full traceability” turned out to be a lot number that pointed to a shipment from a third-party reseller, not the original manufacturer.
I want to say the fail rate was 5%, but I might be misremembering. The point is, it was enough to quarantine the whole batch and stop production on our new monitor.
Our quality manager—who had warned me about this twice—just looked at me and said, “Kemet components. Authorized distributor. Next time.”
He was right. I only believed that advice after ignoring it and eating the cost.
What the “Cheap” Option Actually Cost
Let me break down the math. (Should mention: I built a TCO spreadsheet after this, and it's now part of our procurement policy.)
For 2,000 capacitors:
- The cheap option: $0.31 each, or $620 total.
- The Kemet T491 option: $0.42 each, or $840 total.
- Price difference: $220.
That $220 is the kind of number that catches a procurement manager's eye. But here's what I didn't calculate the first time around:
- Quarantine and inspection labor: about 6 hours of engineering time.
- Rework on the failed boards: 14 boards, two of which needed full rework.
- Replacement components: the Kemet T491 parts we ordered anyway.
- A new multimeter: $150, because the old one couldn't do ESR testing.
- Two weeks of delayed product launch.
Add it up, and that cheap batch cost us somewhere around $4,200 in extra labor and materials. I don't have the exact invoice in front of me—this was Q2 2024—but the number is close. The $0.42 part ended up being way cheaper than the $0.31 part.
So, bottom line: price per part is not the same as cost per working board.
Why Kemet T491 for a Blood Pressure Monitor?
You might be thinking, “Tantalum capacitors are nothing special. Why would a brand matter?”
Good question. I asked the same thing. Here's what our lead engineer explained:
According to the T491 Kemet datasheet (kemet.com), these are surface-mount tantalum capacitors with MnO2 technology. They're designed for general-purpose applications, but the key for us is consistency. We need parts that match the datasheet every single batch, because a medical device isn't the place for surprises.
A blood pressure monitor has to be reliable. If a capacitor fails on the power rail, the device might give an incorrect reading or fail entirely. In a hospital, that's not a minor inconvenience—it's a patient safety issue.
I'm not a regulatory expert, but under FDA 21 CFR 820, our quality team has to verify suppliers and keep traceability records. With the T491 Kemet parts from an authorized distributor, the documentation was straightforward. With the other vendor, we didn't get much more than a packing slip and a promise. (Source: FDA 21 CFR 820).
I should add that buying from an authorized distributor doesn't just mean paperwork is easier. It means the part is less likely to be a counterfeit or a rejected unit sold on the secondary market. And for a medical device company, authentic components are non-negotiable.
What I'd Do Differently (and What I'd Keep)
If I could go back to Q2 2024, I wouldn't have made the initial mistake. But since I did, at least the lesson stuck.
Now our procurement policy requires:
- At least two quotes for passive components, but always check total cost, not just unit price.
- Authorized distribution for anything that goes into a medical device.
- Incoming inspection with a multimeter that measures capacitance and ESR on a sample of every lot.
That last one—the multimeter—might sound like overkill for a capacitor order. But after this experience, the best multimeter for electronics in our budget is part of the standard toolkit. It paid for itself in an afternoon of testing.
And the T491 Kemet series? It's still our go-to for that blood pressure monitor design. Not because it's the cheapest, and not because Kemet is the only tantalum capacitor manufacturer out there. It's because the total cost of ownership is lower. We know what we're getting. The datasheet matches reality. The traceability exists.
To be fair, the other vendor might work fine for a consumer gadget with less risk. I'm not saying all non-Kemet components are bad. I'm saying that for our company, in this application, the cheap option wasn't worth the gamble.
Take the TCO Spreadsheet Seriously
If you're a procurement person reading this, I know the pressure to hit a cost target. I've been there. The line item cost on the PO is what your boss sees. The rework, the delays, and the stress don't show up on that same report.
But they show up somewhere. Our $220 savings turned into a $4,200 lesson.
So, next time you're comparing quotes for Kemet components—or any component—ask yourself one question: what does the lowest price actually include? Shipping, setup, testing, rework, field failures. If it doesn't include all of those, it's not the real price.
Prices I mentioned here are based on distributor quotes from January 2025; verify current rates before you make a decision.
