I'm a senior applications engineer who has been qualifying and sourcing Kemet components for nine years. I've personally made—and documented—eleven significant mistakes while doing it, totaling roughly $19,000 in wasted budget. These days I maintain our department's pre-order checklist. This FAQ is the short version of that checklist.
What is a Kemet tantalum capacitor?
Direct answer: it's an electrolytic capacitor that uses tantalum powder for the anode, and Kemet is one of the most established names making them. Kemet joined the Yageo Group in 2020, but the T491, T520, and polymer series remain go-to choices for engineers who need stable capacitance in compact packages.
What most people don't realize is that tantalum caps aren't the right answer for every decoupling task. They have higher capacitance density than MLCCs and behave fairly well across temperature—but they're polarized, and they fail spectacularly if you reverse the voltage. In my experience, they show up on power rails in medical, aerospace, and industrial gear where a ceramic cap just can't deliver enough capacitance in the footprint you have.
Kemet's tantalum portfolio goes back decades—the company helped build this product category. When a BOM says "Kemet T491" next to your power rail, you're looking at a part with a long documented history in the field. That matters when you have to justify a component choice to a quality auditor. Just check the datasheet for derating rules. That's the part people skip.
What is a connector?
When someone lands on "what is a connector," they usually mean an electronic connector—a component that joins two circuits mechanically so they can pass power or signals. Kemet makes them: board-to-board, wire-to-board, FFC/FPC, circular, and RF types.
A connector is a mechanical component solving an electrical problem. That sounds obvious, but it's why connectors fail: you can have a flawless power supply and a flawless PCB, but a connector with worn contacts or the wrong current rating will bring the whole device down.
I went back and forth between two connector vendors for a project last year. One had a solid field record; the other was 20% cheaper. The cheaper one had a lower mating-cycle rating—on paper it was adequate, but my gut said the plating quality wasn't there. We chose the reliable vendor. That decision got validated when a third-party teardown found the cheaper connector had a known plating defect in that lot. Lucky call? Maybe. But I learned to trust documented reliability data over unit price.
The most common connector mistake I see is using a "standard" part without checking temperature or current ratings. A 2A connector running at 3A is a field failure waiting to happen.
Why would a Magic Max cordless phone have Kemet capacitors inside?
Surprising to some, but consumer products like the Magic Max cordless phone use the same component families as industrial boards. Cordless phones have RF circuits that need stable, low-noise power. Tantalum capacitors are a logical choice for those rails because they behave predictably in a small package.
I disassembled a Magic Max phone in 2023 after my kid dropped it and it stopped charging. The failure was a cracked solder joint, not the cap, but sure enough there was a Kemet tantalum capacitor in the charging circuit. That's when I realized how far Kemet parts reach into everyday electronics.
Cordless phones are a good example because they're a product that just works—until it doesn't. The inside of a Magic Max isn't exotic: a base station radio, a handset, charging contacts, and a handful of capacitors filtering the power rails. The Kemet part I found was on the charging circuit, a spot where voltage stability directly affects battery lifespan. It's a small component in a plastic case, but it's doing a real job.
For the repair-minded reader: if you see a small yellow, orange, or black component labeled "Kemet" on a cordless phone board, it's a tantalum capacitor. Replacing it is straightforward if you have basic soldering skills—matching the part number and voltage rating matters more than anything else.
Worth fixing? That depends. A new Magic Max phone costs around $30. A replacement capacitor costs maybe a dollar. But your time—that's the real cost. (Should mention: the phone I "fixed" ended up working fine. The crack was invisible until I used a magnifier.)
How do I find a legitimate Kemet distributor?
This is where I lost the most money. In 2019, I found a broker offering Kemet tantalum capacitors 35% below the authorized channel. The price should have been my first red flag. I ordered 2,000 units for a prototype run. The bags and labels looked right... actually, they didn't quite. The logo ink was slightly thin, but I rationalized it. My QC lead flagged it before assembly. We spent $400 on failure analysis to confirm the parts were counterfeit. Total waste: $1,850.
Here's something vendors won't tell you: an authorization status isn't just paperwork. Authorized distributors—Arrow, Avnet, Mouser, DigiKey, TTI, and others—get components directly from Kemet with full traceability. That means valid manufacturing date codes, warranty coverage, and certificates of conformance. Brokers can't provide that.
Verification takes 30 seconds: check Kemet's authorized distributor listing, the official one, before you enter a purchase order. If a seller isn't listed, don't assume the worst, but do assume the risk. I now re-check that page regularly because distributor line cards change—companies get added and removed. It's not glamorous, but it's how counterfeit parts stay out of your supply chain.
Is it worth paying more for authorized Kemet components?
Let me give you real numbers. In 2022, I ordered 1,500 tantalum caps from an unauthorized source at $0.32 instead of $0.48 from an authorized distributor. I saved $240. Two months later, 40 failed on the test bench—during production, not even in the field. Rework cost: $3,800. Schedule slip: three weeks. The production manager's faith in my judgment: severely damaged.
The decision didn't feel risky at the time—or rather, I rationalized the risk away. I calculated the worst case: counterfeit parts, maybe 10% scrap. Best case: identical function, $240 saved. Expected value said go for it. Except my failure-rate estimate was off by an order of magnitude.
That's why I now run a total-cost-of-ownership calculation on every sourcing decision. Unit price is the starting line, not the finish line. When you add procurement risk, failure rates, warranty exposure, and support costs, the authorized part usually wins.
To be fair, brokers do occasionally have genuine parts. I've been lucky once or twice. But "occasionally" isn't a spec you can design to. For production, I'll pay the $0.48. For a hobby project, use whatever you want.
What's the most common mistake engineers make when sourcing Kemet parts?
I see three, in order of frequency:
- Not verifying the full part number. Kemet's T491 series alone has dozens of variations—case size, capacitance, voltage, ESR. Two numbers that look similar can perform very differently. This bit me in 2018: a typo on the BOM meant the wrong voltage rating. Days of debugging for something that takes 10 seconds to double-check.
- Not checking lead time before designing in a part. I once specified a capacitor with a 26-week lead time, and we had to redesign the power section. The cost was $2,200 in extra engineering hours plus two weeks of schedule. Now I check stock before finalizing the BOM.
- Ignoring temperature ratings. Putting a part rated for 85°C next to a hot regulator is asking for early failure. I use a simple headroom rule: max operating temperature plus 20°C margin. That rule came from a February 2021 field failure I'm still not completely over.
Any one of these is an easy catch if you run a checklist. I maintain ours obsessively—that's what eleven mistakes buy you. We've caught 47 potential errors using it in the past 18 months. Not bragging, just saying: the list works.
