Search found 595 matches

by NleahciM
Sun Oct 30, 2011 3:08 pm
Forum: SparkFun Product Questions
Topic: Breakaway female headers
Replies: 4
Views: 575

Re: Breakaway female headers

Female headers are generally not breakaway - only the male ones are. You can get them in 2-36 positions (single increments). Look for Sullins brand at Digikey. You can't cleanly break them like you can some pin headers -but you typically can cut a long one to the size you want by sacrificing a pin.
by NleahciM
Fri Oct 14, 2011 6:14 pm
Forum: SparkFun Product Questions
Topic: Using a camera flash circuit...
Replies: 4
Views: 759

Re: Using a camera flash circuit...

Hey All, I was looking into using a camera flash circuit for a project, and I came across this tutorial on HowStuffWorks. http://electronics.howstuffworks.com/camera-flash2.htm All the logic in this circuit makes sense to me except for the rectifier diode. Did they do that circuit up wrong, or is s...
by NleahciM
Tue Sep 13, 2011 4:28 pm
Forum: PCB Design Questions
Topic: Arbitrary shape trace resistance
Replies: 4
Views: 1857

Re: Arbitrary shape trace resistance

I think some high-end CAD packages (such as Altium) will do that, but the actual resistance will always vary due to manufacturing tolerances (mainly the thickness of the copper plating). Most of the time a "back of the envelope" calculation would be sufficient anyway... I do not believe Altium has ...
by NleahciM
Tue Jul 19, 2011 3:36 pm
Forum: PCB Design Questions
Topic: SMD inductor soldering
Replies: 9
Views: 2876

Re: SMD inductor soldering

phalanx wrote:Hot air guns are not ideal for devices like that since the heat is coming from above and they have a large thermal mass.
Exactly. It is entirely the wrong tool for the job.
by NleahciM
Tue Jul 12, 2011 5:59 pm
Forum: PCB Design Questions
Topic: Milling out a BIG hole in the PCB
Replies: 5
Views: 1866

Re: Milling out a BIG hole in the PCB

All of them just like you would any other hole. The only time you would have a hole on select layers would be blind or buried vias. That isn't exactly true. He wants a rectangular hole. And he probably wants it not to be plated. This would typically be on it's own layer, or on the same layer as the...
by NleahciM
Fri Jul 08, 2011 2:24 pm
Forum: PCB Design Questions
Topic: USB-A-PCB usage in practice...
Replies: 8
Views: 4311

Re: USB-A-PCB usage in practice...

With card edge connectors you typically have the golden fingers selectively gold plated a significant amount so that they can handle a large number of insertion cycles. This is fairly expensive and most quick turn PCB houses cannot do this and will either no bid the PCB or have somebody out of house...
by NleahciM
Wed Jun 15, 2011 11:01 pm
Forum: SparkFun Product Questions
Topic: Lithium Ion Battery Usable voltage range?
Replies: 3
Views: 427

Re: Lithium Ion Battery Usable voltage range?

Dutch2 wrote:Should the design include something that will prevent the unit from discharging the battery too far?

D2.
Absolutely.
by NleahciM
Tue May 31, 2011 1:14 pm
Forum: SparkFun Product Questions
Topic: source for cheap strain gauge?
Replies: 6
Views: 2101

Re: source for cheap strain gauge?

I've heard of people making their own, ie something like this.

I haven't tried it myself, but my understanding is that you can get decent results from this method.
by NleahciM
Tue May 24, 2011 2:59 pm
Forum: PCB Design Questions
Topic: Square pads vs round pads - does it matter?
Replies: 10
Views: 3257

Re: Square pads vs round pads - does it matter?

I just noticed that my plastic stencil is cut wrong. Despite the GTP layer having all the needed holes in it, the stencil has only things that are square. That got me thinking. All the pads for my surface mount resistors, capacitors, LEDs and such (size 0805) are round. Had they been square they wo...
by NleahciM
Mon May 16, 2011 3:19 pm
Forum: PCB Design Questions
Topic: Trace width/Thickness?
Replies: 12
Views: 2397

Re: Trace width/Thickness?

geome wrote:The problem with that, slag, is I plan on measuring measuring current through the trace, also. Multiple traces complicates that. =/
Are you planning on using a shunt resistor or using the actual trace as your resistor?
by NleahciM
Wed May 11, 2011 9:13 am
Forum: PCB Design Questions
Topic: Trace width/Thickness?
Replies: 12
Views: 2397

Re: Trace width/Thickness?

I did try that, but there are some things that bothered me. Some people I work with have a board that is rated at 30 amps, but there aren't any traces that are ~430 mil as the calculator suggests would be necessary for that (at a fairly standard 3 oz/ft^2 thickness). Is the issue that I need to con...
by NleahciM
Sun May 08, 2011 3:30 pm
Forum: SparkFun Product Questions
Topic: Small 'wire to board' connector?(to save soldering external)
Replies: 7
Views: 700

Re: Small 'wire to board' connector?(to save soldering external)

The problem with connectors like this and the one MichaelN posted is it is very difficult to properly crimp the contacts for the mating plug unless you spend a lot of money on the appropriate crimping tool. -Bill Thanks guys....those picoblade look ideal, so I'm gonna buy one of these.... http://cg...
by NleahciM
Thu May 05, 2011 10:09 pm
Forum: PCB Design Questions
Topic: Soldering TQFP-100 Repeatability
Replies: 8
Views: 2596

Re: Soldering TQFP-100 Repeatability

Are you saying that the IC is moving during reflow? Or is the problem that the IC is not self centering itself during reflow? Or something else? I haven't had problems with reflowing TQFPs of this size as long as they're placed properly. However, it is important to get it placed properly before ref...
by NleahciM
Wed May 04, 2011 8:46 am
Forum: PCB Design Questions
Topic: Soldering TQFP-100 Repeatability
Replies: 8
Views: 2596

Re: Soldering TQFP-100 Repeatability

I was wondering if I could get some tips on how to reliably solder a TQFP-100. I am using a Kapton stencil to stencil to apply the solder paste. The issue that I am having is the when I reflow the solder paste, the chip doesn't align properly on the pads. It is like the chip is shifting between the...
by NleahciM
Sun May 01, 2011 11:21 am
Forum: PCB Design Questions
Topic: Open Hardware logo
Replies: 4
Views: 1147

Re: Open Hardware logo

that's good that design still does not fall into the category of standards and everyone is free to choose their own that conforms more to own taste. Moreover, as you can imagine, this process is akin to the evolutionary order and there is open source, where ones can use ideas of other and make thei...