the PROBLEM it that none of us own a big Company.
so it's better to stock up the shack with the best

I hate to be the one to break the news to you but the diode mfg
doesn't really care much about the 10 diodes you are going to buy -)
They are going to mfg what the big company wants to buy.

On Wed, 3 Sep 2003 10:39:33 -0700, "Bob"
wrote:

Lower voltage rectifiers are easier to make and therefore cheaper. Further,
they have lower forward drop and are faster. No point in using too high a
rating if these other factors are worth considering.

While the 1 kV 1N4007 is definitely a different creature (with some
PIN diode characteristics) compared to the lower voltage 1N4001-1N4006
rectifiers, I very much doubt that they make separate wafers for
1N4001, 1N4002 etc. but instead try to make, say a 500 V rectifier.

My guess is that they just measure the reverse leakage voltage at
various voltages and print a different label, based on these
measurements. Those passing only the 50 V test will be labelled 1N4001
and sold at a slightly lower price and so on.

If there is a huge order for 1N4001 and there is not enough 50 V units
produced, some units tested OK for 100-500 V are labelled 1N4001 to
full fill the large order. Thus, some selected 1N4001 parts may work
even above 100 V.

Paul OH3LWR

On Wed, 3 Sep 2003 10:39:33 -0700, "Bob"
wrote:

Lower voltage rectifiers are easier to make and therefore cheaper. Further,
they have lower forward drop and are faster. No point in using too high a
rating if these other factors are worth considering.

While the 1 kV 1N4007 is definitely a different creature (with some
PIN diode characteristics) compared to the lower voltage 1N4001-1N4006
rectifiers, I very much doubt that they make separate wafers for
1N4001, 1N4002 etc. but instead try to make, say a 500 V rectifier.

My guess is that they just measure the reverse leakage voltage at
various voltages and print a different label, based on these
measurements. Those passing only the 50 V test will be labelled 1N4001
and sold at a slightly lower price and so on.

If there is a huge order for 1N4001 and there is not enough 50 V units
produced, some units tested OK for 100-500 V are labelled 1N4001 to
full fill the large order. Thus, some selected 1N4001 parts may work
even above 100 V.

Paul OH3LWR

Dick Carroll; wrote:

W7TI wrote:

On 3 Sep 2003 10:13:00 -0700, (Mike Silva) wrote:

Another question resulting from too much time on my hands. Why do we
have rectifier diodes (e.g. 1N4xxx, 1N54xx) with different voltage
ratings? Other than the voltage rating I don't see any differences on
the data sheets I've looked at. Why not just make and use 1kv diodes
alone?

73,
Mike, KK6GM

__________________________________________________ _______

$$$

--
Bill, W7TI

Yep. And I'd wager if one did breakdown tests on a variety of diodes many would show the
same specs regardless of their different markings.

Another pet peeve-
Several times I've seen failure of low voltage capacitors which were run too close to
their ratings for comfort, IMO. Like 16 vdc rated on a 13.8 DC line in mobile gear.
Spikes are sure to take 'em out eventually, it would seem. Why designers do that I've
never understood, and I never replace them as rated, but use 25 or 30 volt caps. Never had
a problem from doing that, and no repeats.
I remember years ago troubleshooting a dead board in an Atlas 210 transciever that had a
shorted - leaky 16 volt rated electrolytic across a 13.8 dc line on the board. But it
still had enough internal resistance that it didn't smoke anything, just killed the
operation of the board.

I cussed the (unknown) designer of that thing for awhile! /:-D))

Dick,

Electrolytics should be run near their rated voltage to "form" properly.
The spikes should be taken out by a parallel 100nF cap, or clipped by a
zener.

Rob

Dick Carroll; wrote:

W7TI wrote:

On 3 Sep 2003 10:13:00 -0700, (Mike Silva) wrote:

Another question resulting from too much time on my hands. Why do we
have rectifier diodes (e.g. 1N4xxx, 1N54xx) with different voltage
ratings? Other than the voltage rating I don't see any differences on
the data sheets I've looked at. Why not just make and use 1kv diodes
alone?

73,
Mike, KK6GM

__________________________________________________ _______

$$$

--
Bill, W7TI

Yep. And I'd wager if one did breakdown tests on a variety of diodes many would show the
same specs regardless of their different markings.

Another pet peeve-
Several times I've seen failure of low voltage capacitors which were run too close to
their ratings for comfort, IMO. Like 16 vdc rated on a 13.8 DC line in mobile gear.
Spikes are sure to take 'em out eventually, it would seem. Why designers do that I've
never understood, and I never replace them as rated, but use 25 or 30 volt caps. Never had
a problem from doing that, and no repeats.
I remember years ago troubleshooting a dead board in an Atlas 210 transciever that had a
shorted - leaky 16 volt rated electrolytic across a 13.8 dc line on the board. But it
still had enough internal resistance that it didn't smoke anything, just killed the
operation of the board.

I cussed the (unknown) designer of that thing for awhile! /:-D))

Dick,

Electrolytics should be run near their rated voltage to "form" properly.
The spikes should be taken out by a parallel 100nF cap, or clipped by a
zener.

Rob

Other than the voltage rating I don't see any differences on
the data sheets I've looked at. Why not just make and use 1kv diodes
alone?

=================================

Because somebody like you would complain about no 2kv diodes being
available.

Other than the voltage rating I don't see any differences on
the data sheets I've looked at. Why not just make and use 1kv diodes
alone?

=================================

Because somebody like you would complain about no 2kv diodes being
available.

"Reg Edwards" wrote in message ...
Other than the voltage rating I don't see any differences on
the data sheets I've looked at. Why not just make and use 1kv diodes
alone?

=================================

Because somebody like you would complain about no 2kv diodes being
available.

Like me in what way? Curious? Uninformed? Ignorant? Whipped with
extension cords as a child? Raised by circus performers? Eats
mayonnaise out of the jar when depressed?

Come to think of it, why the heck *aren't* there any 2kv diodes
available?!

And how come I can't buy air-variables for a buck down at the corner
electronics store?!

73,
Mike, KK6GM

"Reg Edwards" wrote in message ...
Other than the voltage rating I don't see any differences on
the data sheets I've looked at. Why not just make and use 1kv diodes
alone?

=================================

Because somebody like you would complain about no 2kv diodes being
available.

Like me in what way? Curious? Uninformed? Ignorant? Whipped with
extension cords as a child? Raised by circus performers? Eats
mayonnaise out of the jar when depressed?

Come to think of it, why the heck *aren't* there any 2kv diodes
available?!

And how come I can't buy air-variables for a buck down at the corner
electronics store?!

73,
Mike, KK6GM

Like me in what way? Curious? Uninformed? Ignorant? Whipped with
extension cords as a child? Raised by circus performers? Eats
mayonnaise out of the jar when depressed?

=====================================
Mike, you and I have much in common. I really do sympathise. Pleased to
make your acquaintance.
---
Reg, G4FGQ