can we use SCHOTTKY RECTIFIER instead of Rectifier diodes - Electronic Circuits Projects Diagrams Free

nikhil arora · 10th April 2006, 12:46 PM

what are the advantages or disadvantages when i use
1N5822 or similar instead of 1N4001 or similar

**Nigel Goodwin** · 10th April 2006, 01:04 PM

Quote:

Originally Posted by nikhil arora

what are the advantages or disadvantages when i use
1N5822 or similar instead of 1N4001 or similar

There are some people who consider that they generate less noise?, but I can't comment on it being true or not?.

Personally I don't see any advantage, and I wouldn't consider using them for normal low frequency mains rectifiers.

justDIY · 10th April 2006, 02:46 PM

Nikhil, is this for your smps project?

You'll deffinately want to use a schottky instead of a gp silicon rectifier ... I've tried it both ways, and the schottky works a lot better - it is almost always recommended that way in the datasheets as well.

**Nigel Goodwin** · 10th April 2006, 02:51 PM

Quote:

Originally Posted by justDIY

Nikhil, is this for your smps project?

You'll deffinately want to use a schottky instead of a gp silicon rectifier ... I've tried it both ways, and the schottky works a lot better - it is almost always recommended that way in the datasheets as well.

If it's for a switch-mode supply you must not use a conventional rectifier, they are too slow and rapidly fail, however that wasn't what he asked? - unless he asked it very poorly?.

Oznog · 10th April 2006, 04:27 PM

The downside is that Schottky does not have as sharp an IV curve. That is, higher currents make the voltage drop a bit higher. While it turns on at 0.3v, at high currents a Schottky can drop more voltage than a std rectifier, up to 1v or more. This is a somewhat inaccurate generalization however since it depends on the rated current of the Schottky. A current that drops 1v on a 1 amp Schottky might drop only 0.3v on a Schottky rated for 20 amps.

Schottky diodes DO have higher reverse leakage current, potentially much higher. The magnitude increases with the device's current rating, temperature, and reverse voltage. If it is a battery charger for example, this could drain battery current backwards into the transformer secondary winding in a significant way. It could drain the battery when the device has been turned off.

nikhil arora · 13th April 2006, 07:44 AM

I have read some where that Schottky diode produce greater emi noise as they switch on and off rapidly.

**Nigel Goodwin** · 13th April 2006, 09:26 AM

Quote:

Originally Posted by nikhil arora

I have read some where that Schottky diode produce greater emi noise as they switch on and off rapidly.

If this is for conventional mains rectification, why would you want to use a Schottky anyway?.

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10th April 2006, 12:46 PM	(permalink)
nikhil arora	can we use SCHOTTKY RECTIFIER instead of Rectifier diodes what are the advantages or disadvantages when i use 1N5822 or similar instead of 1N4001 or similar __________________ MSc Electronics Unexperienced ;-)

10th April 2006, 02:46 PM	(permalink)
justDIY	Nikhil, is this for your smps project? You'll deffinately want to use a schottky instead of a gp silicon rectifier ... I've tried it both ways, and the schottky works a lot better - it is almost always recommended that way in the datasheets as well.

10th April 2006, 04:27 PM	(permalink)
Oznog	The downside is that Schottky does not have as sharp an IV curve. That is, higher currents make the voltage drop a bit higher. While it turns on at 0.3v, at high currents a Schottky can drop more voltage than a std rectifier, up to 1v or more. This is a somewhat inaccurate generalization however since it depends on the rated current of the Schottky. A current that drops 1v on a 1 amp Schottky might drop only 0.3v on a Schottky rated for 20 amps. Schottky diodes DO have higher reverse leakage current, potentially much higher. The magnitude increases with the device's current rating, temperature, and reverse voltage. If it is a battery charger for example, this could drain battery current backwards into the transformer secondary winding in a significant way. It could drain the battery when the device has been turned off. __________________ I thought what I'd do was I'd pretend I was one of those deaf-mutes.

13th April 2006, 07:44 AM	(permalink)
nikhil arora	I have read some where that Schottky diode produce greater emi noise as they switch on and off rapidly. __________________ MSc Electronics Unexperienced ;-)