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#electronics

28 posts26 participants4 posts today
Public
Graham Sutherland / Polynomial

if you've been using yaqwsx's JLCPCB parametric search tool (or have been stuck using JLC's regular parts search page) I can highly recommend checking out this forked version: dougy83.github.io/jlcparts/

it uses a new database storage approach which makes component updates orders of magnitude faster, and it comes with some additional quality of life features too. I've also got an open PR on it to significantly improve the coverage of parametric data extraction.

dougy83.github.ioJLC Component Catalogue
#electronics
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C.

I really hate that I have to say this, but this was just supposed to be a funny story. "Chinesium", "yum cha", and "Short Fiction" were clues.

I'm aware that because a market for substandard but drastically cheaper parts exist, more of those substandard parts are made available. Stuff that failed QA, so called "third shift" output, salvaged parts, inventory that fell off the back of a truck, etc.

And I think this is a *good* thing.

When I was doing my final-year project at school (Computer Engineering Technology), there were no cheap Chinese sources for parts. There were a couple of electronic supply houses in town that cost an absolute fortune. The cheapest way to get parts was DigiKey. I got four of my classmates together to do one bigger order, to get quantity discounts and split the shipping charge.

Plain through-hole resistors in common values were $0.25 -- each. After minimal income tax at minimum wage, that meant I could work for an hour and afford maybe 12 resistors. Virtually everything else was measured in dollars apiece. It cost a bloody fortune just to build my project (a computer-controlled slot machine).

I'd always been interested in hobby electronics, but I and many others simply couldn't afford to participate.

Now I can go on AliExpress and order an assorted kit of tens of pieces of each of dozens of common values of 10% resistor for four bucks, including delivery. A hundred dual FET op-amps for ten bucks.

1/2

#electronics#hobby#parts
Public
C.

Line manager: Uh, Boss?

Boss: Yes?

L: We finished that new run of the component. We sent it to QA.

B: Okay? Is there a problem?

L: I just got the report back. This batch, uh, didn't meet the tolerance goal.

B: [rubs temple] Okay, shit happens. I guess it goes out as 10%. That's not too bad a hit.

L: Uh, it didn't meet 10% tolerance, either.

B: What? How bad is it? 20%?

L: Uh...

B: It's *worse* than 20%?

L: Most of the parts are barely within 50% tolerance.

B: ...

L: So, uh, we should probably ...

B: Who was running the line?

L: ...

B: It was Chuck, wasn't it?

L: ... yes.

B: Was he drunk again?

L: I don't know. I sent him home.

B: Nobody's made these components in 50% tolerance for thirty years. Where am I going to sell them?

L: ...

B: Okay, AliExpress it is. Go to the noodle shop across the street and offer him some new boxes if we can have the ones his supplies come in. No way I'm putting these parts and the company name in the same room together.

(inspired by some parts I received today...)

#electronics#hobby#AliExpress
Public
Dr David Mills

Hey you!
Yes you. Have you checked the batteries in the thing you haven't used for a while? No? Do it now, or as soon as possible.

This toot brought to you by a bunch of leaking Duracell and Poundshop Kodak batteries in some kit I was going to take to work today.

#battery#electronics
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C.

The best part? My cost for manufacturing the boards and shipping them to me in Canada (from China), with all applicable duty and taxes included, brings them out to about $1 per board.

I may try other designs at some point. But I can't see myself going back to the uber-expensive ones that are commercially available.

I can't wait to try one of them!

3/3

Screenshot from a Printed Circuit Board (PCB) layout program showing the design of my perforated prototyping board.
#MakeDontBuy#design#custom
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C.

When building electronics project for permanent use - i.e. after testing on a solderless breadboard - you normally go to a #soldered perforated board of some type as a #prototype, or even for very-low-volume production.

There are different types of boards. I dislike "matrix" boards, which are just isolated pads on a grid, i.e. there are no connections between any of them. Some people swear by these; I swear at them.

I prefer protoboards that have multiple holes per pad (so you can connect multiple component leads without having to add an explicit wire jumper). If they've also got #busses - sets of pads that run the whole length or width of the board - so much the better!

Some are #crap: laminated paper PCBs where the pads lift off the board if you even try to desolder something you added. Row/column labels missing, or (like I found with some recently) that don't line up between the front and back of the board 😆 , or most egregiously, they don't actually show the pad pattern on the front of the board, so you have to keep flipping it to check your parts are correctly placed. One example below.

I have some from "BusBoard Prototype Systems" that I like. The SB4 is a 38 x 24 (912 hole) board that is #snappable into quarters. Two of the quarters have rows that are 4-hole, 2-hole, 4-hole. The other two are 5 2-hole pads. Both types have a single bus running along each of the 2 long sides.

But ...

1/x

A scan of the underside of a cheap perforated prototyping circuit board - "protoboard" or "perfboard" - showing its pattern of pads and holes, along with the brand/model name "Radio Shaek 2". :wink: This is a typical crappy generic Chinese board, made from laminated paper. The copper pads are very thin and the glue holding them to the board isn't great, so they lift off the board very easily when soldering, or especially desoldering. The holes aren't very well centered in the pads. There's no soldermask, so it's easy to get accidental solder bridges. The board is browish tan, and has an 18 x 24 grid of holes, so 432 holes total. There are 2 continuous busses running up the middle of the board. On either side are rows consisting of (from outside to in) a 2-hole pad, three single-hole pads, and a 3-hole pad.
#electronics#hobby#ProtoBoard
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