1. BITX20@groups.io

Re: SMD Group Build

Jack, W8TEE
 

I wish someone would put together an assortment of, say, 40 common values, quantity 100 of each value and market it for some reasonable markup for resistors and caps. For the club build, I'd prefer 1206 since this is a huge step for some of the club members.

BTW, today I just got 40 clear plastic 1.25"x0.75" cosmetic sample jars (eBay #332506418787). Tomorrow I'm going to Target and buy Velcro sticky tape "dots" and place one half on the bottom of the jar, and the other on a piece of plywood which hangs on the wall. Now if somebody has an assortment of 40 common values, they go into the jar and I'm ready to go. Each jar will have a small Avery label on it.

Jack, W8TEE


From: Diver Martin <diver.martin@...>
To: BITX20@groups.io
Sent: Thursday, January 25, 2018 12:09 AM
Subject: Re: [BITX20] SMD Group Build

Jack,

Just as a point of reference:  Going for 5% tolerance 1k ohm resistors, and buying 1000 at a time, a quick search on digikey gives me:

1000x 0603 resistors:  $2.07
1000x 0805 resistors:  $3.03
1000x 1206 resistors:  $4.63

For reference
1000x axial TH resistors: $7.29.

At a half penny a pop, the cost of 1206 vs 0603 I'm betting isn't going to be a noticable difference.  (At 100qty, they're about 2x as much, ~$0.01 each, or $1 for 100).  You can really sneeze hard and not loose a lot of money.



On Wed, Jan 24, 2018 at 8:20 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:
I can barely see a 0603! I would prefer 1206 if I can find them and am not too worried about the cost differential.
Jack, W8TEE

From: Clark Martin <kk6isp@...>
To: BITX20@groups.io
Sent: Wednesday, January 24, 2018 9:15 PM
Subject: Re: [BITX20] SMD Group Build


Clark Martin
KK6ISP

On Jan 24, 2018, at 5:56 PM, Diver Martin <diver.martin@...> wrote:

Mouser & Digikey are my go-to for SMT parts.  They carry just about everything.  If you have other oddball SMT stuff, and either one are out, head to findchips.com.  There are alternate suppliers, but those two always have what I need, either in the exact specified part number, or an equivalent.  Other places will source 1206's and stuff, but might only sell by the full reel (which I have yet to need, except maybe 0.01uF caps or 0.1uF caps across multiple, multiple projects).

SMD resistors/caps (0603, 5% in my case) are usually cheap enough that I buy them in 1000-piece quantity, because $2 of parts for life or $0.5 for the parts I need for the project, and to always have them on hand, is easy.


I’ve only bought from Digikey a few times but I use Mouser all the time.  Also there are Newark and Allied for such supplies.

I bought a set of 0805 resistors (from 0 ohm through several Mohms) and a set of 0805 caps (10s of pF through 1µF).  They came on cards that fit a day planner binder.  There are between 1 and four strips of 25 each for each value (depending on expected usage levels).  I have little trouble working with 0805 parts and they  fit nicely on .1” grid perfboard (with plated through holes).  

When I use up a strip I buy a new strip of 25 at a local electronics shop (Silicon Valley still has a few).

I haven’t done any PCB fabricating yet but that is in the plans.

SMD diodes and transistors of most any size are easily soldered to perfboard.

I’ve also soldered up to 8 pin SOICss buy putting alternate pins on the perfboard pads and tack soldering leads to the other pins.

It definitely makes for smaller boards.





--
Martin Held - AE7EU
http://ae7eu.com/
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