General > General Technical Chat
Do you hate blue resistors?
<< < (12/13) > >>
Fungus:

--- Quote from: exe on March 26, 2020, 11:16:39 am ---My fears now are ... components smaller than 0402

--- End quote ---

I don';t know the exact size but a guy brought some resistors to Arduino club as a challenge that were about the size of a grain of sand. Drop one on the table and you could easily lose it. I don't even know how a pick and place machine can work with them (anybody?). Is there really a need for components that small?  :-//

(The challenge was to measure the resistance with a multimeter...)


--- Quote from: exe on March 26, 2020, 11:16:39 am ---highly-integrated ICs with many legs

--- End quote ---

That one's actually much easier than it looks: You don't solder each leg individually, you just bathe them all in solder and let the solder mask do its job. If two legs short together you can usually run the iron down between them and they'll separate. If the board is well-prepared with a flux pen then the only real trick is to use the right amount of solder.

(and if you use too much then desoldering braid will fix it in no time)
bd139:
Got to be honest I prefer SMD now. It's much much easier to work with and the parts don't take up as much room in storage. Also they're a lot cheaper!

Couple of prototypes I did same day turnaround:



exe:

--- Quote from: Fungus on March 26, 2020, 12:48:23 pm ---If I used SMD on the board I'd have to order a bunch of duplicate SMD parts, too, so...  :-//

--- End quote ---

For me this is only concern for ICs, as I already have kits of passive components from China, both TH and SMD. For ICs, since they are expensive and sometimes don't come in TH package, I use smd-to-dip converters.

I do very little soldering, most the time I spend in spice simulators and writing code. So, I think I can afford pcb fabrication for projects I do as there are not many.


--- Quote from: Fungus on March 26, 2020, 12:48:23 pm ---That one's actually much easier than it looks: You don't solder each leg individually, you just bathe them all in solder and let the solder mask do its job

--- End quote ---


Sorry, I meant complexity of using them. That is reading lengthy datasheets, programming it or controlling via SPI, esp. initialization, routing traces, power supply sequencing... this sort of challenges. Nowadays even dc-dc converters have built-in mcus and proprietary firmwares... I have a few displays from aliexpress that I couldn't make working. I still don't know if they were dead, or I killed them, or I didn't initialize them properly. Or may be the seller advertised a wrong controller, and I used a wrong datasheet. Sometimes a single instruction, or a single pin tied to a wrong rail can screw it, that's why I don't like sophisticated ICs that do many things at once.


--- Quote from: Fungus on March 26, 2020, 01:05:56 pm ---Is there really a need for components that small?  :-//

--- End quote ---

If they are on sale, then there is a demand :).
unknownparticle:
My electronics life began at the cusp of the IC, and valves were still being used in some applications, you could certainly still obtain them at every electronics store, so what amazes me most about SMD is their obvious tolerance to soldering temperature, both with an iron or especially with hot air.
How do they do that?!
newbrain:

--- Quote from: Fungus on March 26, 2020, 12:48:23 pm ---I'm not afraid of SMD because of the size, I don't use them because almost everything I make is a one-off or in small quantities so drawing a proper PCB, ordering it, waiting for it to arrive, etc., is a non-starter.

--- End quote ---
Same here about one-offs, but I'm using SMD more and more on protoboards: 0805 and 0603 fit perfectly in between 2.54mm pads!
1206, OTOH are too large and difficult to fit.
I very seldom use THT passives nowadays.
ICs get adapter boards (unless they can fit dying bug style - some legs down, some legs up...).

Not the best to look at, but workable if you don't want to wait for a proper PCB.

Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod