Why can't I find a simple 1/4Watt, through-hole, 1K resistor?

[steveFD92A]

Yes, a newbie.  My hobby is IOT stuff around the house, mostly on Arduino or ESP boards plus a few with the Raspberry family.  

My perfboard projects are really messy and easy to make a mistake when soldering.  Plus a board with a dozen parts can take me a half day to assemble.  I would much rather take advantage of low-cost offshore PCB manufacturers and make my projects easier to wire, share and just make them look better.

So, for my first project, I have a Wemos D1 Mini board, an MCP23008 chip, three RGB LEDs and nine resistors.  All through-hole, 0.1" spacing.  Really basic.

I found the Wemos library and the MCP part.  But, how do I find a 1K, 1/4 watt through-hole resistor??  I mean, how basic can it be?

And, I briefly looked for the RGB LED part.  Only because if I can't even find simple, common through-hole resistors, then I may as well give up on using Eagle at all.  The Adafruit library has a common-anode RGB LED part, but my part (DigiKey Part Number 754-1615-ND) is a common-cathode component.  I did find a couple of DigiKey lbr files, but none of them have LEDs.

Why is it so difficult to find parts, even when I have the DigiKey part numbers?

[one-of-the-robs · Accepted solution]

Have you tried looking in the "resistor" or "rcl" (resistor, capacitor, inductor) libraries that ship as part of the standard install?

Eagle's libraries don't sort resistors by power because it's never been reliable to say how big a 1/4W resistor is. Instead, they declare the package by physical size, as that's what you're designing your board to accept. Here, for example, is an 0207/12 package

0207/12 resistor

That's a fairly typical 1/4W to 1/2W size. You'll find it in RCL as "R-EU 0207-12"

[steveFD92A · Accepted solution]

Thanks for the response.
I hope that you can understand my frustration.  I have been using components for more than 50 years from the days that a "standard" resistor was a 1/2 Watt axial part. The only further options were 1% or 5%.  (1/4 Watt was relatively rare).  The last time I made a PCB, I used sticky pads and red tape on mylar. Our first computerized system cut the red rubylith layer from the mylar backing. ****, I'm old.

It would have never occurred to me that "CF14JT1K00" is a 1K resistor. Is there a Rosetta Stone or other universal translator that I am missing here?  I really don't understand why "resistor 1K" shouldn't produce some search results that I could sort through. But nothing?

Searching for the DigiKey part number, CF14JT1K00CT-ND, doesn't result in a find even though it contains "CF14JT1K00".

But, I've given up on finding exact parts for my short-run projects. I'll simply find something with the hole spacing I need and change the part number and value. For example, my project uses a 5mm RGB common-cathode LED. I actually found one (just one) in the libraries (Adafruit.lbr), but it is common anode. Since I am not doing simulations and the footprint is the same, I am using that part on my schematic. I haven't looked for it yet, but I hope that I could just copy and edit that library to turn the LEDs around to make them common cathode and save it as a new part.

So, deciphering your suggestion of "R-EU 0207-12". Tell me if I understand this: R= Resistor, EU= European package (Are European parts really different from US parts)?  0207, I am guessing that this is the body size of 2mm x 7mm, and -12 is the lead spacing?

I recall one of the online tutorials I saw said that I need a caliper. I need to go back to that tut again.

However, I still find it incredible that I can't search for "resistor 1K".

I realize that this is a different topic, but since I tend to use the same dozen or so parts on every project, is there a way that I can put the parts that work for me into a private library? Is it really as simple as copying the part's .stl file into my private library folder?

Again, your response is appreciated.

[one-of-the-robs · Accepted solution]

OK, first off, why do you expect to have to search for a resistor by value? Until you actually populate the BoM for ordering, a 1K 0.5W resistor is indistinguishable from a 2M2 0.5W resistor. In fact, some PCB design software expects you to start drawing your schematic without even knowing the resistor rating or package.

Eagle binds the schematic and board layout quite closely, so you need to pick a package when adding a part to the schematic. For ICs that often means you pick the exact variant from the list. However, for generic parts like resistors, you don't specify the value in the library - otherwise the library would need a separate part for each of the possible W24 6-decade sequence! Instead, you pick by size, then assign the value with the "value" command.

Again, why would you expect a CAD program sold by AutoDesk to have everything sorted by Digikey's part numbering system? What about those of us who buy from Rapid, or Farnell, or RS, or Mouser?

To the R-EU 0207-12 decoding: Yes, R means resistor. EU means European symbol - the Europeans and Americans have tended to draw different things on the schematic - not package. 0207 is the body size and 12 is the lead spacing.

If you don't like Eagle's library structure you can build your own just to your liking. However, once you get your focus away from "I want to search by value" to the correct "I need to pick a package for the board", the standard libraries aren't that bad.

[steveFD92A]

Thanks.  As I said, I am still learning and I do find your explanations enlightening.

I understand your logic but it does sound circular to me.  Even so, consider my viewpoint as a new user coming from old-style methods of PCB design where the whole world of resistor types could fit on one page, and have room at the bottom.  The engineer draws a schematic, and the BOM would say "resistor 1K, 1/4W", and that was all the PCB designer needed.  But it still boggles me that a search for "resistor 1K" returns nothing, but "resistor" returns hundreds.

As I find the parts that work for me, I copy them into a private library (myLib) for future quick-find.  Can you tell me what field the "search" looks at in the parts database?

[kennethRVGJ2]

Select the checkbox (Pads, SMD, Description) above the search bar to choose which fields search