Alt-BEAM Archive
Message #06729
To: beam@sgiblab.sgi.com
From: jester96beam@iname.com
Date: Wed, 13 Oct 1999 20:43:38 -0400 (EDT)
Subject: [alt-beam] Re: PCB etching
You can also get etch resistant pens (probably from radio shack) which work well. Etching usually takes around 10 minutes.
I usually draw the layout on paper first (as most people do). But then I tape the paper to the PCB and center-pop the holes on the copper side through the paper, then drill them. Then draw on the tracks.
After you've made a few boards, you'll find it's quite easy.
Chris
---- you wrote:
> You need Copper Clad board, etching solution, something like steel wool
> or fine sand paper to clean the board before working on it. You'll also
> need a resist. the Easiest resist is paint or fingernail polish remover.
> Radio shack sells rub on patterns, but the lines don't always hold. I
> recomend getting a dry transfer kit from radio shack and use the pin
> hole pads and the IC pads for the holes, and then for the lines, use
> paint (acrilic craft paint is good, and you can peel it off) or
> fingernail polish (you'll need acetone fingernail polish remover to get
> it off, but it's easy to work with).
>
> When done making your patern, use a GLASS, PLASTIC, OR RUBBER container
> to pour heated etching solution into (It'll eat through metal). Put the
> board in and allow it to etch for the proper amount of time. Time can
> vary depending on temperature and how new the solution is. Expiriment!
>
> Chris wrote:
> >
> > Is there any way to hand etch PCB? What do I need to do it? About how much will it cost? Are there any tutorials on the web?
> >
> > Win a LAPTOP Computer and get your FREE E-mail Account at http://mail.chek.com
>
> --
>
>
> Richard Piotter
> richfile@rconnect.com
>
> The Richfiles Robotics & TI web page:
> http://richfiles.calc.org
>
> For the BEAM Robotics list:
> BEAM Robotics Tek FAQ
> http://people.ne.mediaone.net/bushbo/beam/FAQ.html
>
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6730 Thu, 14 Oct 1999 10:53:15 +1000 [alt-beam] Re: 3904 & 3906 Question .... beam@sgiblab.sgi.com Elmo Hi Rik
Yeah i got a bit confused about this to.
I often use the 2N3904 and 2N3906 but as well i have a supply of BC546
and BC556 (Philips) transistors.
The answer to your question in short is that not all transistors use the
same pin out. To the best of my knowledge they all seem to use the
middle pin as the Base but the Collector and Emitter pins vary between
Manufacturers.
The 3904's and 3906's have E,B,C when looking at them with the flat side
facing you.
The BC546 and BC556 are C,B,E when looking at them with the flat side
facing you.
Elmo
Rik wrote:
>
> I purchased some 3904 & 3906 Transistors from Digi-key (fairchild) pt#
> 2N3904-ND / 2N3906-ND
>
> AND WHAT IM WONDERING IS ...
>
> reading the pins from left to right ... with the flat side facing me...
> do they go: E,B,C ??
>
> here's the link if needed to the digi-key pdf. catalog page featuring the
> parts in question.
> http://www.digikey.com/EC/V2/204.pdf
>
> i only question this because i read somewhere else that all transistors are
> E,C,B from left to right...and i thought that was odd (well..i read it in a
> book from radio shack) .
>
> Any help would be great!...im getting ready to breadboard my parts!..... im
> just waiting to get my solar cells in the mail so i can get testing..and
> then building!
>
> thanks,,,,Rik
>
> www.geocities.com/mutantb0y
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