1N4007 quandry

[Randall]

I can buy 100 1N4007 1000v 1A diodes for about $5. I can't think of a reason why I would want to buy a 1N4001 or 1N4002, or any other lesser rated diode, so why are they even made, since the 1N4007 can do everything the smaller ones can? Is it simply a penny saving equation in mass production? Does it cost less to make a 1N4004 than it does a 1N4007?

[Enzo]

If you buy the diode by the billion - and yes, companies do - a difference of 1/100 of one cent is a $100,000 savings.

Does it cost more to make? I have no idea.

There are designs that specify a specific part, not just something that works. Using other than specified parts may void a contract. Especially with government work. Even if the "wrong" part is perfectly OK electrically.

And you are right, I have zero reason to buy anything but 1N4007 for my stock.

[olddawg]

Weight and dimensions can be a consideration especially for a aerospace applications. For general bench repair applications... not so much.

[Jazz P Bass]

"so why are they even made?"

I believe it's called 'engineering'.

[Randall]

"I believe it's called 'engineering'."

That doesn't really help me at all.

[Chuck H]

"I believe it's called 'engineering'."

That doesn't really help me at all.

Well... Part of what he was saying is that when someone needs a component that's spec'd for the task, it can be designed and the cost defined. In some cases (as noted, size or weight can factor into this) this is the best route for one reason or another. I think the other part of what he may have been saying is that without engineering spec parts engineers wouldn't have a job!?! So, of course they happily do it whenever requested again and again. Sometimes regardless of a suitable part already existing. Their employer says "I need a part that can do this." That guy knows even less about what's already available. So the engineer does what he's asked and gets paid. Both aspects are very real.

[Jazz P Bass]

I don't know, I was thinking more along the lines of "what does the part have to do (deal with).
Meet the design criteria.
Pick the part.

You certainly wouldn't make a comment like "why are there so many different fuse values."

I agree, for repairing amps, 1N4007 is a good all around choice.

Then again, would you want an 1N4007 in placed of a 1N4148?

[Randall]

"You certainly wouldn't make a comment like "why are there so many different fuse values.""

Of course not, a 5 amp fuse would never be a substitute for a 1 amp fuse. So that is apples and oranges for this discussion. The question is if 1N4007 gets the job done, AND IF size and weight aren't in play, why make 6 other lesser rated versions. Just seems silly to me. Maybe that is engineering, I don't know.

[Chuck H]

"You certainly wouldn't make a comment like "why are there so many different fuse values.""

Of course not, a 5 amp fuse would never be a substitute for a 1 amp fuse. So that is apples and oranges for this discussion. The question is if 1N4007 gets the job done, AND IF size and weight aren't in play, why make 6 other lesser rated versions. Just seems silly to me. Maybe that is engineering, I don't know.

Look at it this way... There are probably a dozen guys on this forum that have performed repairs on request for a customer with an amp that had a DNR (do not repair, as in, do not BOTHER to repair) only because it was a tight fit between repair and value vs. buying another amp. It would be easy to default, but then the customer has to wait a little (or a lot) longer and no one gets paid. I think that sometimes engineering can be like that. In the end you give the boss/customer what they want. Maybe you end up with marginal redeemed value, but beans must be counted. It's what we do. So we have a thousand diode models where perhaps one may be suitable. JM2C

[g1]

I think a historical perspective may be more appropriate. I'd assume the voltage rating was a big challenge to overcome originally. And the price difference for the higher voltage was probably much greater. At some point they may as well have discontinued the lower voltage part and superceded with the 4007, but then is when you get into the problem of requiring the original spec'd part as mentioned in posts #2 & 3.

[loudthud]

See my comments in this thread: http://music-electronics-forum.com/t31954/

[Dave H]

I thought it was so they could still sell the parts which didn't meet the 1N4007 speck as 1N4004, 1N4001 etc.

[J M Fahey]

so why are they even made,..... Does it cost less to make a 1N4004 than it does a 1N4007?

Probably.
Money runs the Wiorld so they are even slightly cheaper, or slightly easier to make or have lea smaller rejection percentage, all 3 parameters can be turned into $$$ for comprison.

FWIW I buy 1n4002 by the Thousand, and use them everywhere as clippers, distortion, *signal* rectification, biasing, thermal sensors, etc. , *except* as power supply rectifiers because my bread and butter are 100W SS amps and 1N400x are useless in that role, my standard rectifier (also bought by the 1000s) is 1N5402 .

I do have a few (say a 100 unit bag which lasts years) 1N4007 for, you guessed it, tube amp repairs, the odd Tube build (not very cost effective for me, I prefer SS) and some Line powered stuff.

So you see, different conditions, different needs.

Or look at it the other way: there must be massive sales for each type or they wouldn´t be made, period, although In guess the bulk must be 1N4002 for the zillion small power supplies, wall warts, etc. with way less 1N4007, because when you need HV capability, you need it.

Haven't seen or been offered a 1N4001 for 30 years or so, and doubt 1N4004/4005 are even made today.

FWIW TIP2x/3x/4x transistors which used to be offered in no/A/B/C/D letters for 40/60/80/100/120V ratings, for the last 10/15 years have been offered as "C" variants as the "preferred" one, it says so in the catalogs.

So in a nutshell: if there is even a small $$$$ difference, different versions will be made, if they meet somebody´s needs.
Don´t dig deeper because there is not much more than that. IMHO of course.
Calling Electronics competition "cutthroat" is the understatement of the Year

[Old Tele man]

It's called "PRICE POINT" and engineering's task is to DESIGN circuits using the LEAST costly components needed to achieve the original design.

[bob p]

A friend of mine works in the semiconductor industry as a chip designer. When they started making multi-core processors they started off getting quite a few failures from fabrication. As an example, if they were making quad-core chips, some would pass the 4-core test coming out of fab while others would not. Those quad cores that had a bad core or two used to be culled. Then he came up with the idea of rebranding those culled multi-core processors as good processors with a smaller number of cores. Many dual core processors are actually 4-core rejects. He got a patent for that re-binning idea. If you ever wondered where a 6-core CPU came from, it was supposed to be an 8-core, but it failed so they binned it as a 6.

a lot of the time "lesser" rated products are just performance variants of one product that meet different perf levels, so they get binned into specific performance levels. All RAM chips are sorted this way. They don't bother to make low-frequency RAM chips. they try to make all high-frequency RAM chips, and the ones that don't perform up to spec get rebranded as lower performance products.