onlymeeee

Using higher rated voltage rectifier diodes
« on: January 05, 2009, 10:25:30 AM »
Hi,

Are there any downsides to using 1N4007 in all situations as it can work in all of them but has a higher rated voltage?

I'm not sure on things like this because I have heard differences in opinions, particularly with using higher voltage caps. (Most people agree it is fine. Whereas, I have also read Geoff Tanner's opinion that it isn't good to put higher voltage electrolytics into lower voltage circuits as they don't get enough polarisation.)


hobiesound

Re: Using higher rated voltage rectifier diodes
« Reply #1 on: January 05, 2009, 11:06:53 AM »
as far as i know the only restriction with using higher rated DIODES is that the diode is physically bigger.

but then again i might be wrong.  ::) :o

adamasd

Re: Using higher rated voltage rectifier diodes
« Reply #2 on: January 05, 2009, 11:49:43 AM »
Quote
as far as i know the only restriction with using higher rated DIODES is that the diode is physically bigger.

Through hole 1N4007 is the same size as a through hole 1N4001 last I looked. Although I switched to just using the 1N4007 for low and high voltage years ago, works for 95% of my power rectification.

For your voltage rectification needs 1N4007 will work just as well as 4001.
so there

onlymeeee

Re: Using higher rated voltage rectifier diodes
« Reply #3 on: January 05, 2009, 01:33:27 PM »
Quote
as far as i know the only restriction with using higher rated DIODES is that the diode is physically bigger.

Through hole 1N4007 is the same size as a through hole 1N4001 last I looked. Although I switched to just using the 1N4007 for low and high voltage years ago, works for 95% of my power rectification.

For your voltage rectification needs 1N4007 will work just as well as 4001.

May I ask what happens on the other 5%?  Do you use a lower 1N400x? If so why? or is that you just use a completely different kind?

gyraf

Re: Using higher rated voltage rectifier diodes
« Reply #4 on: January 06, 2009, 12:30:32 AM »
my guess: the last 5% is probably higher-than-1A-current applications

Yes, if you have a batch of 1N4007, you won't need any 4001-4006.

Jakob E.
..note to self: don't let Harman run your company..

adamasd

Re: Using higher rated voltage rectifier diodes
« Reply #5 on: January 06, 2009, 03:53:51 AM »
Quote
my guess: the last 5% is probably higher-than-1A-current applications

Lets call that 4.6%. Once in awhile I use a bridge instead of discrete, even if it is under the 1A rating of my bag o 4007s. They have that hole in them so you can bolt them to the chassis. Bolt to the chassis with the legs sticking up and you get heat sinked, (spell checks wants me to use sunken) heat sunken rectifier and power supply board mount all in one. Although this is generally complete overkill, especially since you need to hop up to 4+ Amp rectifiers to even get that mounting hole. Works great for DC/regulated heater supplies when all you need to put on that board is a few low volt parts. One hole gives you a very stable mount for the bridge and the bridge gives you 4 big fat legs to mount the board on.
so there

onlymeeee

Re: Using higher rated voltage rectifier diodes
« Reply #6 on: January 06, 2009, 07:49:52 AM »
Ok cheers.

I guess I'll just get a batch of 1N4007s.  I'm just wondering why the 4001-4006 even exist then?

adamasd

Re: Using higher rated voltage rectifier diodes
« Reply #7 on: January 06, 2009, 02:54:18 PM »
Sometimes we reverse bias a diode, in that case a 4007 may not be the best choice. This is also why I said

"95% of my power rectification needs"

Sometimes we reverse bias a diode, and a high PIV is not always good for that.

Edit: I previewed that before posting and did not even notice my repetition.
« Last Edit: January 06, 2009, 02:56:13 PM by adamasd »
so there

onlymeeee

Re: Using higher rated voltage rectifier diodes
« Reply #8 on: January 06, 2009, 03:09:55 PM »
Oh ok i see.  I'm not that confident yet with spotting when its a reverse bias, so maybe I'll stick to what's specified. 

For the G1176, is there 2 in reverse bias? (for the full wave rectifier?)  So is it better if I use what is specified? (1N4003)

PRR

Re: Using higher rated voltage rectifier diodes
« Reply #9 on: January 07, 2009, 02:39:31 AM »
> wondering why the 4001-4006 even exist then?

Back in 1971, a 4007 was EXpensive, and often hard to get. The target was apparently 4006, and the process was still funky enough that there were a lot of weak rejects to unload as low-rated 4001-4003 parts.

If you buy ten-thousand today, you may find partial-penny price differences, or you may not. Same supplier, same boxed-reel packaging:
1N4001 10,000 $0.017 
1N4006 10,000 $0.017 
1N4007 10,000 $0.052 
 
However buying "just one", I can find 4001 at $0.48 and 4007 at $0.41. The part costs 2 to 5 cents in huge cartons, ten times that much for onesies. There's NO logical reason that 4007 costs 7 cents more than 4001. So buying just a few is mostly handling charge and accumulated round-off error in layers and layers of re-pricing from large box to loose part.

And that $0.41 price drops to $0.30 if you buy a ten-bag, $0.18 if you invest in a hundred. Find a good deal on a pile of 4007 and use it for all 400x applications.


onlymeeee

Re: Using higher rated voltage rectifier diodes
« Reply #10 on: January 07, 2009, 08:27:55 AM »
Thanks PRR.  I can get hold of 50 1N4007 for fairly cheap so am wondering whether I could use them in all 1N400x applications without any consequences.

adamasd mentioned that when he reverse biases a diode, higher rated voltage is not always good.  Would you recommend me avoiding the 1N4007 in this case?

adamasd

Re: Using higher rated voltage rectifier diodes
« Reply #11 on: January 08, 2009, 12:06:18 PM »
Quote
adamasd mentioned that when he reverse biases a diode, higher rated voltage is not always good.  Would you recommend me avoiding the 1N4007 in this case?

I was referring to non power rectification uses. just stick with the 4007 any time you need to turn anything under 1000Volts and 1 Ampere from AC into DC.
so there



 

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