Cool Customer Application

It's not all that often that we get to see or can talk about just what is done with the boards we build at Screaming Circuits. In most cases, it's a proprietary product or some government thing. But, recently we built some boards for NTH SYNTH. They have a successful Kickstarter project to produce a music synthesizer. They describe it as: "It is fun to use, sonically-rich, and hackable by design." Go check it out.

Nthsynth-small-007

[This image is from their website] I had wanted to take some photos for them of their PC boards being assembled on our SMT machines, but the boards ended up being built on one of our night shifts and I missed the chance.

Duane Benson
They're the people out there turnin' music into gold
But hopefully makin' more than Jim Bass' two-fifty for an hour

 

Electrolytic Ambiguity

I've written about ambiguity a few times before, like this post about fiducials. But I'm not talking about the PC board today. I'm talking parts. More specifically, I'm talking about silk screen markings for your parts on the PCB.

CapacitorsDiodes have a lot of opportunity for ambiguity, as you can read here. There are many ways to mark parts, but fewer ways to clearly mark them. Take a typical electrolytic capacitor. It can be thru-hole, smt metal can, tantalum, or a few other form factors. The capacitor manufacturers aren't doing any of us any favors where markation is concerned.

Check out this image. Yikes! In all cases shown here, I've oriented positive on the left, which, according to IPC is pin 1. This is also the zero degree rotation for the centroid value. But, isn't it nice of those component manufacturers to put the identification bar on the positive side for tantalum capacitors and on the negative side for metal can electrolytics? Not!

So, how should you mark this in the silk screen on your PCB? For an electrolytic capacitor, the best approach is to mark the positive sided with a (+), plus sign. If you mark pin 1, with the number 1, it can easily be mistaken for the minus sign. If you mark the negative side with a minus sign, it can easily be mistaken for pin 1.

For a metal can capacitor, it is also acceptable to put the notched outline in silk screen. We still recommend that you place the (+) plus sign on there too.

Duane Benson
I'm just positive I put the negative right on the left

Happy Independence day!

Images As usual, we are closed on Independance day, July 4th. This means that the day won't be counted toward your turn times. For example, if you have asked for a 48 hour turn time and we received your kit on the afternoon (past the receiving cut off) of the 3rd, your 48 hour clock will start on Thursday, the 5th.

We apologize for any inconvenience and wish you a happy holiday.

Retrospective

The other day, I needed just a few things at the grocery store which, given the small town I'm in, should have been a quick no-stress fifteen minutes. But, some kids were sitting in the middle of the first intersection I came to and didn't seem to want to move out of the way of my five thousand pounds of rolling danger. Traffic at another intersection was backed up due to a train. On the next block, I had to follow someone, likely looking for an address, at about ten miles per hour. Then there were pedestrians crossing the street far slower then human body mechanics are designed for. In the store, it seemed like every isle I tried to go down was blocked by carts or people. The "short line" at check out turned out to be short because a customer and checker were having payment issues. The drive home was much like the drive in. In short, there was nothing short about the trip. Nor was there anything low-stress about it.

But this is a blog about electronics stuff. It's not a shopping blog or a driving blog. The point is, that trip reminded me of projects I've been involved in years ago. Someone changes a spec after that part of the design is complete. The only version of a key component on the approved vendor list has a 12 week lead time. It's Friday, at 4:00pm, the board files have to be shipped off by five, but there's still several hours of double checking left to do. While placing the prototype parts order, you keep getting distracted by loud talking in the background.

Ugh. Not only is such a thing blood pressure raising, but it also can lead directly to problems any of us would never dream of letting out the door. Like these here:

Too little time can cause problems. So can too much stress and distraction. There's not always a good solution, but anything to reduce stress and agravation while doing final checks is probably a good thing.

Duane Benson
Is there "lab rage" like there's "road rage"?

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