For hobbyists, why buy 1N4001 diodes when you can buy a 1N4007?

[jolshefsky]

This is something that has puzzled me for a long time. Why would anyone these days buy a 1N4001 diode and not a 1N4007?

Background information: the 1N400x series is a basic silicon diode useful for things like power rectification or input protection for up to 1A current. The 1N4001 has a breakdown voltage of 50 volts. 1N4002: 100V, 1N4003: 200V, 1N4004: 400V, 1N4005: 600V, 1N4006: 800V, and 1N4007: 1000V. The other electrical characteristics are the same.

So if I were shopping for diodes, if I was doing some kind of low-voltage supply, I might pick the 1N4001. But then if you're a hobbyist, you might want to rectify mains voltage someday, so you'd want 600V. Or maybe you've got a use for a 1000V breakdown. If you're stocking your home supply, why not just buy 1N4007 and use them for everything?

The only thing I can think of is the price. But looking at DigiKey, the price for a single Fairchild 1N4001 is US$0.18, and for 1,000, it's US$0.03646 each. The 1N4007: US$0.18 for 1, US$0.03646 for 1,000.

I'm stumped!

[Richard Crowley]

I had heard (but cannot find the reference now to confirm) that 1N4005 and up are made on a different (high-voltage) semiconductor fab process which has different HF and capacitance characteristics than the lower-voltage 1N400x series. Of course, if you are using these only for bog-simple, ordinary mains-frequency linear power supplies, it probably doesn't make any difference.

[Zero999]

The 1N4005  and up have a lower capacitance.

[David Hess]

I had heard (but cannot find the reference now to confirm) that 1N4005 and up are made on a different (high-voltage) semiconductor fab process which has different HF and capacitance characteristics than the lower-voltage 1N400x series. Of course, if you are using these only for bog-simple, ordinary mains-frequency linear power supplies, it probably doesn't make any difference.

High voltage rectifiers are often or always fabricated using a PIN structure which also makes them useful as voltage variable capacitance, PIN, and snap-off diodes but you would have to qualify them yourself and they tend to have high capacitance because of large junction size.

The higher voltage diodes also have higher forward voltage drops and usually slower recovery times but those should not matter in the applications that the 1N400x series are used in.

As to why the lower voltage ones even exist, sometimes a low and specified breakdown voltage is desired so they can do double duty preventing over-voltage but in this case, I suspect it is just because they can be sold and someone will buy them.  I only keep 1N4004s or higher available for general repair work.