I can cite a counterexample:
- Don Klipstein ( snipped-for-privacy@misty.com)
too, right? lol
I spent the last twenty plus years working with both floppies AND mil spec resistors, and am aware of the manufacturing processes used in their making. You?
too, right? lol
...but you have a problem answering the question?
too, right? lol
I worked with enough mil-spec resistors, though for a minority of the past 22 years. If you worked with them as you said, you should be able to mention how a 1/4 watt through-hole mil-spec one from 1986-1987 (when I stuffed and soldered a lot of military boards) looks different from a commercial grade 1/4 watt one from that era or now.
- Don Klipstein ( snipped-for-privacy@misty.com)
With a little hunting, one could easily get a much better than half off price for the 1/2M piece buy the they offer/quote.
Is there such a thing as a 5% SMD resistor? I mean... I know there is, but aren't they like really hard to find right now?
too, right? lol
For the mil spec, there was more than one package style. The most common were epoxy packaged in a dark brown epoxy, and marked alpha-numerically, not with color coding, as the commercial variety are.
The other style were glass encapsulated, alpha-numerically marked, and the typical base color was a dark blue.
Again, however, it does vary from maker to maker.
J-STD through hole is still available, however, for SMT, since mil 2000 went away, and everything is, for the most part IPC-A-610 for acceptability, pretty much all SMT resistors are the same, unless one wants or specs a very specialized, or tightly controlled variety.
That's not the point. The point was that a single penny savings on a large volume production means a LOT of money saved.
Now go price through hole parts at .25 W.
An addendum:
A lot of folks use through hole as the PCBs are usually cheaper, and the manufacturing process usually is as well.
Not if you pay less than a penny for 1%. Even Digikey sells 1% 0603s for 0.45 cents each, a single reel at a time.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
The post I responded to was where you claimed a bigger price difference between 5% and 1%, and now you are arguing about unavailability of 5% vs.
1% for SMD resistors, and a lot of products are now made with SMD components including resistors.Only a couple years ago I ran into a contract manufacturer quoting shorter lead time if I restricted values of 0603 size SMD resistors to what they called "standard values", which were the ones that 10% tolerance resistors had. I suspect the contract manufacturer had a PCB subcontractor that stocked the E12 or whatever it is "10% tolerance values" though nowadays 5% tolerance resistors are "The Usual Stuff". It appears to me that the "usual low cost stuff" among resistors are ones of 5% tolerance but cheaper and quicker if the values are restricted to the
12-per-decade ones that were made with 10% tolerance.How about Digi-Key on a 5% tolerance 0603 size SMD 1-K resistor:
That is a competing product that appears to me to be priced basically 6% higher in larger quantities, available from Digi-Key.
- Don Klipstein ( snipped-for-privacy@misty.com)
You can buy resistors labeled 5%, but they're usually really 1% or better. Laser trimming costs the same.
We just buy 1% resistors, to keep our parts lists shorter. There's no point to stocking, kitting, and placing 1K 5% and 1K 1% resistors on the same board.
John
material, too, right? lol
Looks like you did/do not know a quick-to-see characteristic of 1/4-watt mil-spec through-hole resistors about 21 years ago, that discerns them from 1/4 watt "commercial grade" ones, when I stuffed and soldered 1/4 bazillion of them (actually merely 10's of thousands).
I give you another chance to say before I do what this difference is or was when I worked with plenty of them.
- Don Klipstein ( snipped-for-privacy@misty.com)
Cheaper PCB for through-hole? Why and how and cite? It costs more to drill holes!
For that matter, I have used ExpressPCB enough times, and occaisionaly encountered their surcharge for drilling more than however many holes per square inch of PCB.
- Don Klipstein ( snipped-for-privacy@misty.com)
material, too, right? lol
Fuck you. Read it again. The mil are/were alpha-numerically marked, and the commercial grade are color coded stripes.
Fuck you and your chances.
I wouldn't care if you croaked first.
And I told you, asswipe.
The mil that *I* used were hermetically sealed glass encapsulated OR epoxy encapsulated, and were marked alpha-numerically, and has NO metal crimped end caps for terminations, and had premium quality leads. They had both value tolerances as well as thermal derating tolerances marked on them.
Commercial through hole are standard metal film on ceramic tubes with metal end caps and glazing fired over that (ie NOT glass), then color coded with stripes to include three significant digits, a multiplier, and a value tolerance code. They are cheap Tin plated copper leads. The metal end caps are crimped on an they typically do NOT have thermal derating stripes on them. (6 band) jobs do.
You're an idiot. ALL PCBs including SMD have holes.
Ever heard of a via? They are ALSO plated through.
Most through hole, simple boards are only two layers, and that is almost always cheaper than a board with internal layers.
You are wrong. I've done at least a couple of SMD boards myself that have had no holes at all. It is quite possible.
Dave.
Rick Nungester snipped-for-privacy@mail.com posted to sci.electronics.design:
Well, 33 *was* one of the standard values at a time when only about four were available at 20% or something. It is grandfathered into the 10%,
5%, 1%, etc lines to this day. IIRC 22 is another. Also, each E-series of a particular tolerance includes all the values of the series of next greater tolerance and produces the geometric means of all adjacent values to roughly double the available values as well as halving the tolerance. Assuming the tolerance is taken to mean a ratio of standard deviation ( or some multiple thereof) to the mean, the statistics for the series combination seem to differ from that of the parallel when synthesizing a composite of mean closer to an off standard value. Care to elaborate on this?
Granted, but it is NOT common at all.
Not uncommon for clad aluminum PCBs used in power applications.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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