Claimed "1/4 watt" through-hole resistors from Amazon seller "Eamasawa"

[Simon]

who cares what the parts are made of? what are their specs? I find myself annoyed by the categories on the distributors sites, I don't care what the resistor technology is, I'll select the parameters I want and what I get I get.

[eti]

who cares what the parts are made of? what are their specs? I find myself annoyed by the categories on the distributors sites, I don't care what the resistor technology is, I'll select the parameters I want and what I get I get.

"Who"? Is there a universal answer to that? No. I think the engineers desinging Royal Navy torpedoes might care *A LOT*.

You sound somewhat impatient - why would that "annoy" you; would you rather they HID such detail? I am sure you're pretty much alone there, if so.

[Monkeh]

who cares what the parts are made of? what are their specs? I find myself annoyed by the categories on the distributors sites, I don't care what the resistor technology is, I'll select the parameters I want and what I get I get.

The method of construction is one of the specs. Resistors are not all equal.

[amyk]

Test their resistance and capability to withstand 0.25W. If they are within tolerance and dissipate 0.25W fine, they are fit for the purpose. The fact that the leads are thinner should not be a factor, because you didn't buy resistors specified by their lead diameter.

[Simon]

who cares what the parts are made of? what are their specs? I find myself annoyed by the categories on the distributors sites, I don't care what the resistor technology is, I'll select the parameters I want and what I get I get.

The method of construction is one of the specs. Resistors are not all equal.

But what specs does the construction affect? I look for a value, tolerance, ppm, wattage and temperature ratings, I expect that to automatically filter the right type of resistor. Same with capacitors although the construction is a bit more in my face there. I don't say "oh I need a polymer", I say "I need low ESR therefore I should look to a polymer", I don't use polymer because I want to use polymer. If I could filter caps of all types and i wanted ultra low ESR naturally the polymers would come at the top of results, if I filtered ot price the standard aluminiums would came on top.

[Siwastaja]

Simon is fundamentally right, you should primarily look at specs, and let the manufacturer choose the best internal materials and construction techniques to achieve the specs; it shouldn't matter.

This being said, it really does not hurt to understand what goes into manufacturing of parts, because the spec sheets may fail to capture some important or difficult-to-put-in-numbers parameters.

I have observed that many engineers, especially of older generations, do tend to rely too much on their intuitive generalization based on the "types" or "construction techniques" of the parts, and rules of thumb thereof. "Use a high-ESR capacitor at regulator output for stability." vs. almost all modern regulator ICs from the last 20 years are stable with zero ESR. The problem is, this unofficial data gets old; while spec sheets don't lie (except when they do lie!).

But it would be stupid not to augment your design process with such experience, just keep the main focus on the actual data instead of generalizations and always be ready to challenge your own generalizations.

[Simon]

I read all chip datasheets very carefully especially regulators. Some say don't put more that "x µF" some say make sure the ESR is over this or under this. Of course it depends on what you are designing for. I usually have to work with -46 to +85-125 depending on location so what the thing is made of really falls out in the wash of the search. I spent 2 days picking inductors and capacitors for a switch mode regulator, but I will just use descriptive codes for resistors like 1kR_0805_1%_100ppm_-55/+125C and let the assembly deal with that. For bread boarding it really does not matter.

[Simon]

I have not too long ago heard completely contradictory views on tantalum's cause there is a mix of what modern parts do and what older people remember them as being some decades ago. I avoid them anyway based on price.

[SilverSolder]

Making a cost optimized product that still works well is a worthy engineering challenge.   Choosing components that do the job well and reliably, while not costing much, probably requires "bending the rules" a little - the trick is to bend, rather than break them!  I would guess it takes quite a bit of testing to end up with a good compromise.

[floobydust]

I have not too long ago heard completely contradictory views on tantalum's cause there is a mix of what modern parts do and what older people remember them as being some decades ago. I avoid them anyway based on price.

It's not older people remembering what the parts were like decades ago- it's knowledge that electronic components have many parameters that aren't on the datasheets.
Example is voltage derating tantalums, how much noise they have, their lifetime compared to ceramic capacitors which age as well.
Example is 1/4W resistor voltage coefficient of resistance, difference between alloys on the leads, how much power they are good for in real life.

[Simon]

I was thinking more their total fragility and tendency to easily blow short circuited. Others tell me this is no longer as bad as it used to be and new auto grade ones are fine.

[HobGoblyn]

As someone new to this hobby, the huge choice can be overwhelming.

For example, if I want a 10uf  50v cap, RS gives me a choice of 101 through hole (plus another 76 surface mount).

Sure some of those are the same one in bigger quantities but even so, I end up picking at random and because I’ve read Panasonic are good, if it’s to repair something, I usually choose them.

Even if I tick the 5000 hr filter, I still get 7 different Ones (it lists 14 but duplicated in different quantities) to choose from.

[Simon]

There is a huge variety of parts because of cost. At one end of the spectrum you have requirements for very low and high temperature with very long life, at the other end you have "it just has to last a year". Obviously there is different packaging which create duplicates. RS love to repackage everything where as other will do "cut tape" which is what RS effectively do by repackaging, re-reel give you a reel for and SMD assembly machine with whatever quantity you want or full reel as supplied by manufacturer. For hobbyists purposes you will just want cut tape. re-reeling costs per reel in the case of Farnell £3.50 but if you are an assembly house needing 2500 resistors it's maybe cheaper than buying a whole real of 5'000.

As do different specs my thought experiment is that if you multiply all the specs together you will get a number that represents the price.

[farpa]

Hello, do you happen to know where to obtain the datasheet for these resistors, I have sent an e-mail to the manufacturer but they have not responded.

[EPAIII]

Simple guidance: if you want a quality electronic part, buy from an electronic supply house, not Amazon.

It really is that simple.