Who are good USA electronics/parts suppliers?

daivox · Post by **daivox** » Fri Oct 26, 2007 6:56 pm

RadioShack is overpriced and doesn't sell 74xxx logic IC's, and I'm just now starting to get into hardware design and troubleshooting, and am currently building my workbench. I apparently am not so hot at finding electronic component suppliers that are non-bulk-order and aren't excessively costly. My Google-Fu seems to be weak, and perhaps I just don't know what to look for. I know some of you can help me.

I will be wanting to order discrete logic IC's and the usual assortment of components, as well as things like soldering and testing tools, circuit boards, and a good set of drawers for holding things as well. Where to go, and what not-so-obvious items to get for the beginning electronics nut who is just starting to build a proper workbench?

Thanks in advance for any help you can offer!

GARTHWILSON · Post by **GARTHWILSON** » Fri Oct 26, 2007 7:52 pm

For general parts (logic, memory, sockets, breadboarding materials and tools, etc.), I've used Jameco a lot, as well as Digi-Key and Mouser, and to a lesser extent, Allied Electronics, Newark Electronics, Debco, and JDR Microdevices. The last two are smaller distributors.

Jameco's paper catalog is more convenient to find things in partly just because it's not so big, and yet they have vastly more than Radio Shack does and for a fraction of the cost. Digi-Key has more variations of more specialty ICs than you can shake a stick at. It seems like if they only had one of everything in the catalog, the warehouse would be huge-- and yet they stock hundreds or even thousands of each. This makes for great availability, but the prices are a bit higher. Mouser seems to have a bit less in the area of ICs than Digi-Key but more of other things. Newark's website is kind of hard to use, but it gives another place to find things. Allied is good and I do prefer it over Newark, but it's not one of my favorites.

To give you an idea of how much these places have, Digi-Key's and Mouser's paper catalogs are each about 2,000 pages of fine print, and they have nearly all of it in stock. Newark's and Allied's are the same size, but not so fine-print. Jameco is a little more hobbyist-oriented having a smaller catalog with a higher percentage of thru-hole (as opposed to surface-mount) parts, although you don't have to be in the industry to also take advantage of the big ones.

For the 65cxx parts, you can go straight to the source, Western Design Center or buy them from Mike here on this website. Many people don't realize the 65c02 and 65c22 are in production today at WDC and they plan to continue indefinitely.

8BIT · Post by **8BIT** » Fri Oct 26, 2007 8:03 pm

Garth gave many fine choices. Add this one to your list:

Arrow Electronics www.arrownac.com

They may not have every IC, but their prices are low

Daryl

daivox · Post by **daivox** » Fri Oct 26, 2007 8:23 pm

This is AWESOME! You guys are the best. I'm getting excited! :)

My eventual goal is to start working on projects where I design a CPU from discrete logic, much like the infamous Magic-1 project. One thing I have a bit of trouble with is designing the circuits themselves, though; while I can easily make gate diagrams and truth tables and all that jazz, how will I know where I need to be dropping a few select capacitors or resistors? Any suggestions on particular publications that would give a good primer on the nasty details like these? I know that it's not as simple as throwing 100 ICs together directly from the drawings and flipping the switch.

GARTHWILSON · Post by **GARTHWILSON** » Sat Oct 27, 2007 5:15 am

Quote:

how will I know where I need to be dropping a few select capacitors or resistors?

If you're only doing low-speed digital, there normally will be no resistors, and the only capacitors will be power-supply decoupling, ie, from Vcc to ground right at each IC with the connections as short as possible between the body of the capacitor and the body of the IC. With the right construction techniques, you don't even need those, but I'd say just put them in for now since beginners normally violate every rule for good digital layout.

daivox · Post by **daivox** » Sat Oct 27, 2007 2:45 pm

What kind of caps should I use for decoupling? Does it depend on the IC that I use?

GARTHWILSON · Post by **GARTHWILSON** » Sat Oct 27, 2007 5:36 pm

Generally monolithic ceramic, .01 to .1µF. Again, keep the leads short!

daivox · Post by **daivox** » Sat Oct 27, 2007 10:37 pm

So, correct me if I'm wrong, we're basically talking about having the caps as close as possible to flat-out piggybacking every IC that's in use. You said that most beginners completely ignore the rules of good design too; I was curious as to whether you had a moment to elaborate on that, beyond the use of decoupling capacitors. Failing that, is there a book that will answer my questions and get me off the forum? :)

daivox · Post by **daivox** » Sat Oct 27, 2007 10:46 pm

Also, is there a particular logic family that is best suited for these kinds of tasks? I'd rather not find out that I picked up the wrong one after I've already got it in hand...

Nightmaretony · Post by **Nightmaretony** » Fri Nov 16, 2007 7:19 pm

you will WANT to use resistors as pullups for lines pulled high. We made that fun mistake years ago on an arcade game called Sky Shark in which it was a multiple layer board and every pullup went directly to the Vcc internal layer. Talk about nightmare....

smilingphoenix · Post by **smilingphoenix** » Sun Nov 18, 2007 10:44 am

The best logic family for general use these days is probably the 74HC... series of devices. These are CMOS versions of the earlier 74... and 74LS... devices.

If you want to run at high clock speeds, the 74AC... devices are what you need.

GARTHWILSON · Post by **GARTHWILSON** » Fri Nov 30, 2007 11:07 pm

I forgot about the pull-up resistors, but Tony is probably more likely to think of that since he works with a lot of old NMOS parts. I have resistors on things like the I²C interface, annunciator LEDs (to limit the current), and pullups on a keypad.

74HC or HCT is probably the best logic family for you to start with. It's plenty fast for hobby work, but not as fast as 74AC which will be less forgiving of beginners' layout mistakes like excessive wire length and bad grounding schemes.

As for common beginners' mistakes, that is part of a 6502 primer I started a few years ago for this website and never finished. Hardware ones would be like making your address decoding far more complicated and slower than it needs to be, and not taking advantage of serially interfaced ICs (especially I²C and SPI) which are a lot less work to wire up and take a lot less board space. For now, my tips at viewtopic.php?t=342 will help, as will just reading through the forum archives.