Electronics > Beginners
Purchasing parts and basic components for a new lab
bson:
--- Quote from: Dubbie on July 27, 2018, 04:59:12 am ---I use a ton of SMD protoboards. Just cheap ones off ebay. They are great for testing out chips before you order your boards.
Only problem is, is there is a huge variety. The ones I tend to use most are QFNs and SOIC . I also tend to use a bunch of 0.5mm pitch generic ones.
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Yeah, I use the cheap stuff for that as well. Mostly SSOP, SOIC, and occasionally QFN. Just mounted an MSP430i2041 to a QFN-32 adapter though. The main problem with the cheap ones I buy is their tinning is too heavy, but the Hakko FR-300 cleans that up in a heartbeat. It can be hard to place a 0.5mm pitch package when the traces are heavily crowned; it makes parts really prone sliding off the heavy solder before I can get hot air on it (and the air doesn't help). But removing it, pasting, placing, reflow - perfect.
bson:
--- Quote from: tooki on July 27, 2018, 09:07:10 am ---But I agree, as a US resident, you can get stuff fast anyway. One approach to consider might be to stagger, over the course of perhaps a year, your preemptive purchases from Digi-Key into a few orders that each exceed the 50 dollar minimum for free shipping.
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DigiKey's $3.99 USPS flat rate shipping gets to me in 2 or 3 days. If I order just a single device it's usually because I need it right now, and $4... no brainer, I just order it.
tooki:
--- Quote from: ez24 on July 27, 2018, 09:24:07 pm ---
--- Quote from: jpb on July 27, 2018, 08:32:53 pm ---
--- Quote from: ez24 on July 27, 2018, 07:25:56 pm ---They say they use "Preformatted board " not etched. I do not know what this means ? Anyone ?
--- End quote ---
I guess this means perforated board, i.e. board with a grid of holes in (perhaps with copper around each hole).
Perhaps something like this:
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I thought this also but I think perf boards are hard to work with, especially if you have to cut traces. It takes more skill than a normal board.
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Perfboard doesn't have traces. It's just pads — or no copper at all. Are you thinking of stripboard (aka Veroboard)?
And what's a "normal board" to you?!? (There is no generally accepted "normal board".)
tooki:
--- Quote from: ez24 on July 27, 2018, 07:25:56 pm ---They say they use "Preformatted board " not etched. I do not know what this means ? Anyone ?
--- End quote ---
From looking at their documentation, it's stripboard. I assume they 1. chose the wrong English word ("perfboard") for the item, then 2. misspelled it, and then 3. let spellcheck "fix" it to "preformatted board". It's just Chinglish, don't put any stock in it.
E.g. compare https://www.taydaelectronics.com/electronic-kits/100-watt-led-power-meter-with-10-led-steps-for-home-car-or-work-k207-4384.html with its documentation at http://www.taydakits.com/instructions/100w-led-power-meter
Syntax_Error:
So, don't take this the wrong way, it's just a question:
Is there any particular reason you want/need to outfit your lab so extensively this way, as opposed to say an emphasis on developing good simulation skill? Not that the two ideas are opposed or mutually exclusive, because they aren't.
My observation is that your focus is nearly entirely on "the basics" of available parts, which honestly modern simulators all cover just fine, and without breadboard and wiring problems. I mention this partly because of others who may read your thread with interest and be daunted at how much they "need" to buy. There is another way, so to speak.
In my (extremely limited) tinkering experience, most of the devices I need to have on hand at a moment's notice come down to what is needed to interface to whatever I am actually working with, such as microcontroller dev boards. In this case I find myself needing a small assortment of basic resistors and even smaller assortment of capacitors and wires to connect various widgets to a micro. This is just one example.
For most (pretty much all) of my tinkering, I use simulators to feel out the design before I order *anything*, followed by making an initial purchase of parts and passives and dev boards (including SMD breakout boards, etc) and *solder* things together. This is usually the start of a refinement cycle involving more simulation and eventually a PCB and parts order, and more soldering.
I'm not saying this is superior for everyone, but it has a lot of merits, not the least of which is economic. Just something to consider.
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