Jellybeans on us
The true cost of buying your own jellybeans
A 0402 resistor costs less than a cent. So why do engineers dread buying them? Because on a prototype run, the price of the part is the smallest number in the equation.
Most of your parts list is jellybeans
Look at a typical small board: a microcontroller, a regulator, a couple of connectors, a few LEDs, and then dozens of resistors, capacitors and inductors around them. Take a board with 60 parts on it, made from 15 unique part numbers. Ten of those 15 lines are often passives, and they account for most of the 60 placements.
Every one of those lines is its own purchase, its own strip of tape and its own chance to get something wrong.
Where the cost really goes
1. Minimums and extras
For a 10-board run you need ten of each value, plus extras. Pick-and-place machines drop and reject a small number of parts, so assemblers ask for spares, and loading a feeder needs a length of leader tape before the first part. In practice you buy a strip, not ten parts, and most of it comes back to you unused.
2. Your time
Building a cart line by line, matching values, tolerances, voltage ratings and case sizes, double-checking that a 0402 is a 0402 and not the metric 0402 (which is a much smaller 01005), is real engineering time. It's easy to spend an hour on the passive section of a cart. That hour is usually worth more than every passive on the board combined.
3. The risk of one wrong value
One mistyped value or a wrong case size can stop a build. The kit sits until a replacement arrives, and a day or two of shipping for a part that cost a fraction of a cent is the most expensive part of the whole order.
4. Markups when someone else buys them
Full-service assemblers solve the hassle by buying parts for you, but they usually charge for it. Stocking or handling fees on top of the parts price are common. One well-known low-volume service adds 20% to everything it buys on your behalf.
Side by side
| Buying your own passives | Jellybeans on us | |
|---|---|---|
| Cart lines | One for every value | None. Leave them off. |
| Extras for machine loss | You buy and ship them | Ours to worry about |
| Wrong value or size | Build waits for a reorder | Pulled from our stock |
| Leftover strips | A drawer full of cut tape | None |
| Parts cost | Parts, plus any markup | $0 |
So what's left on your cart?
The parts that make your board yours: the chips, connectors, LEDs and anything special. That's usually a short list, and when you request a build we send you a ready-made cart for exactly those parts, extras included.
Bring the chips. We'll bring the jellybeans.
Jellybeans $0, published rates for everything else. Made in the US with world-class ingredients.
Request a buildMore from the bench
What's in the jellybean jar
The brands behind every free passive on your board, from Murata capacitors to Vishay resistors, and why we chose them.
Brands we like to see in your kit
Chips, connectors and LEDs make your board yours. If you're choosing them, these are the makers we'd pick.
Designing for 0402: a practical guide
Footprints, tombstoning, vias, fiducials and capacitor derating. How to lay out a board that builds cleanly with 0402 and larger parts.
How to ship moisture-sensitive chips
What MSL ratings mean, how long a chip can sit out of its bag, and how to pack your kit so nothing needs baking.