1N400X Diodes

[glee]

What is the disadvantage of using 1N4007 in place of 1N4001? That is, why does the range of 1N400X diodes exist? Isn't 1N4007 sufficient for all cases?

[Rerouter]

while it is true that it effectivly does the same job just with a higher blocking voltage i would imagine that back in the 1970's-80's in ten-thousand of quantity i would imagine there would have been enough of a difference to warrent using a lower voltage one,

or perhaps you want your diode to break down over a certain voltage, but at a higher voltage than was available with zeners at the time, from a rare spike event, (seen in some automotive instruments)

[Psi]

The 1N400X is so common that its used everywhere, including in applications where component selection is taken very seriously.

In some products, where a 1N4001 was spec'ed for the original design, the paperwork required and rectification needed to change the component to 1N4007 can be quite expensive.

So manufactures will continue to supply the parts even when better options exist. In some cases the manufacture may have signed a contract to product the component for 20 years or more as a condition for their product being chosen over competitors.

The real question is..
Nowadays, is a 1N4001 is any different to a 1N4007, or is it just the text stamped on the outside
Though they probably are different, as Rerouter pointed out, some applications rely on the breakdown voltage.

[PA4TIM]

I forgot how much because it's a while ago I measured it but there was a difference in Trr. The 4001 was faster if I remember wel. Maybe it is in the datasheet.
4001-4004 are 15 pF and the 4007 is 8 pF but according to other datasheets they are all 15 pF and I can not find Trr in all three datasheets I Looked. Only voltage ratings there differ. For rectifiers I most times use the 4007. They are the same price.

[SeanB]

You will finf Vf is slightly higher and dynamic resistance is higher for the higher rated units. This is unavoidable as to get the high reverse voltage you need to have an initial diffusion that is lower density, so that then the bulk resistance is higher to have a wider junction to withstand the high voltage. Not much difference, but is can be a 100mV at full current, which can be the difference between a long lived diode and a cooked one.

[glee]

You will finf Vf is slightly higher and dynamic resistance is higher for the higher rated units. This is unavoidable as to get the high reverse voltage you need to have an initial diffusion that is lower density, so that then the bulk resistance is higher to have a wider junction to withstand the high voltage. Not much difference, but is can be a 100mV at full current, which can be the difference between a long lived diode and a cooked one.

Ok, but this brings us back to the original question, right? Basically it seems you're saying that 1N4007 is a safer choice.

I hadn't really thought about contracted supply and price differentiation in the "old days" before ubiquitous MIC production, or the change in Zener characteristics since then ... breakdown voltage could be an important consideration too, I see.

The real question is.. Nowadays, is a 1N4001 is any different to a 1N4007, or is it just the text stamped on the outside

Ok, and to extend that idea, is there really added value in paying the difference between a reputable company branded 1N400X and a 1000-for-$10 Chinese supply?

[poptones]

Well, I can remember one time having a product that used about 1000 diodes a box, so we went through lots of 1n4148s. And one time we got a production run that just wouldn't work right. Could not figure it out until we finally tested the diodes. Sure enough, every one just acted like a piece of wire.

I don't know how common that would be now, though, since diodes are less than a cent and it costs 3.8 cents just for a 10cm piece of wire with header crimps on each end. There are lots of more efficient things to counterfeit than diodes.