Screaming Circuits: What's Missing?


What's Missing?

LED cathode There is something about this PCB that will likely cause trouble for anyone assembling it. The first three people to correctly identify the issue get a Screaming Circuits 1GB USB drive.

I know, this day and age, 1 GB doesn't sound like much. But you can still put a bunch of pictures on it. More importantly, you can use it to back up your CAD files just in case disaster strikes your workstation.

This issue is, unfortunately all too common . It's probably a case where the designer knew exactly what he or she was intending and could easily build it up without any problems. However, when sending it out to a third party for assembly, that "in the head" knowledge doesn't help much. If you've got a PCB that you've been assembling yourself and later send out for assembly, make sure you aren't assuming that the assemblers can derive what's hidden in your brain.

Duane Benson
Beware the monsters from Id.


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If I had to solder that LED, I would put the cathode on the LEFT side since the right side is connected to a resistor, hence coming from the microcontroller or circuit. BUT that does not mean it's true, the LED could be "source" instead of been "sink". Or they could of place the resistor on the other side.

SMT Pads around those holes?

Bummer, too late :-)
The anode mark is missing.

Where's the anode? It's on the other side of the cathode... wait...

Silly, but it happens often enough. Keven T, Florin and Josh M - email your mailing address to I won't hang on to it. I'll just use it to mail your your handy USB drive.

Not to repeat everyone, but, yeah, orientation marks. Unless that's, like, C_led (looks like a 2.5 cap footprint in Eagle).

hehe no anode mark, not in copper and not in silkscreen :)

Dude ... where's your anode?

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