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Is this a bridge rectifier for converting AC to DC? — Parallax Forums

Is this a bridge rectifier for converting AC to DC?

rwgast_logicdesignrwgast_logicdesign Posts: 1,464
edited 2013-05-09 20:05 in General Discussion
http://www.st.com/web/en/resource/technical/document/datasheet/CD00074275.pdf

I ordered a few of these and cant figure them out, i'm connecting them to a 28V transformer and getting 11v out. The more I look at that data sheet I only see two diodes and don't see the word bridge so i'm wondering what these are for, hoping I didnt waste my money.

Comments

  • ercoerco Posts: 20,256
    edited 2013-05-05 19:06
    Not a bridge. Per your pdf, it's simply two unconnected ultrafast high-voltage diodes.
  • RDL2004RDL2004 Posts: 2,554
    edited 2013-05-05 20:18
    That's two diodes in one package. How you connect them is up to you. If you have two packages (4 diodes) you could configure them as a bridge rectifier.
  • rwgast_logicdesignrwgast_logicdesign Posts: 1,464
    edited 2013-05-05 20:28
    So why does the data sheet say rectifier? This is where i screwed up
  • ercoerco Posts: 20,256
    edited 2013-05-05 20:45
    Wiki's your friend: http://en.wikipedia.org/wiki/Rectifier

    There are all types of rectifiers. Half wave rectifiers included, which is apparently what you came up with. Four diodes can make a bridge rectifier, so two of your modules can make a bridge.
  • User NameUser Name Posts: 1,451
    edited 2013-05-05 21:07
    And dual diode packs like you purchased are very often used for full-wave center-tapped rectification, which sounds exactly how you have them configured if you're getting 11 V.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-06 02:53
    A diode for high power use is generally a rectifier. You can only convert AC to DC with a diode/rectifier.... think ... think ... think.

    And yeah, there is more than one way to get a full bridge rectifier. This might be very nice for powering a solid-state audio amp.
  • evanhevanh Posts: 15,944
    edited 2013-05-06 04:23
    Loopy Byteloose wrote: »
    You can only convert AC to DC with a diode/rectifier.... think ... think ... think.

    It is possible to rectify without a diode. This is the case when trying to achieve top efficiency by actively switching transistors in place of diodes ... but even then there is usually some diodes (possibly inherent in the transistor) present for backup/startup purposes. They just spend most of their time sitting idle due to the transistors cutting them off.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-06 06:07
    I suspect my terminology is wrong.

    What's a bridge rectifier? Well, I suspect that is a full-wave rectifier matrix of 4 diodes. There is also the full-wave 2 diode solution that has NO 'bridge'.

    And the half-wave rectifier configuration. Maybe more than one.

    ~~~~
    Is it possible to rectify without a diode? I think that depends on what you call a diode. Rectifier tubes are diodes, Amplification tubes are triodes, pentodes, etc.

    Using a transistor to rectify is really using two diodes in an NPN or PNP configuration.

    Then again, there is the 3-phase bridge rectifier.... more diodes.

    http://en.wikipedia.org/wiki/Rectifier
  • kwinnkwinn Posts: 8,697
    edited 2013-05-06 08:15
    A bridge rectifier (also known as a full wave rectifier) is 4 diodes connected to produce a pulsating DC output from both the positive and negative half cycles of the AC.

    A half wave rectifier is a single diode that produces a pulsating DC output from either the positive or negative half cycle of the AC.

    Two diodes can be used with a center tapped transformer to produce full wave DC.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-07 03:31
    Well I found this entry to explain 'bridge rectifier'.

    If seems that two diodes alone are never a 'bridge rectifier' but can be used to create just about any that you might wish.

    http://en.wikipedia.org/wiki/Diode_bridge
  • skylightskylight Posts: 1,915
    edited 2013-05-07 04:15
    Loopy Byteloose wrote: »
    You can only convert AC to DC with a diode/rectifier
    Let's not forget the good old Mercury Arc rectifier:

    http://www.youtube.com/watch?v=KGb-nUK41tc
  • User NameUser Name Posts: 1,451
    edited 2013-05-07 06:35
    Wow, they just don't make them like they used to!
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-07 12:10
    Those were the days... when inventors were found dead in their labs from either explosions, electrocution, or poisoning.
  • kwinnkwinn Posts: 8,697
    edited 2013-05-07 23:15
    Loopy Byteloose wrote: »
    Those were the days... when inventors were found dead in their labs from either explosions, electrocution, or poisoning.

    Ahh yes, the good old days. Good riddance!
  • Heater.Heater. Posts: 21,230
    edited 2013-05-09 03:12
    Loopy,
    Those were the days... when inventors were found dead in their labs from either explosions, electrocution, or poisoning.
    Can you site any examples? I can't think of any.

    I thought about Alfred Nobel and his dynamite, but it was his brother Emil who died in a factory explosion.

    I thought about Marie Curie and her radioactive gloop but she did at least live to the age of 67.

    I guess it's just that the ones who died trying never managed to do enough to become famous.

    P.S Erco. Did you know that Alfred Noble invented plywood? He wasn't an evil monster after all.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-09 11:24
    Madame Currie died of radiation poisoning.
    Tesla went mad and there is much speculation about why. Mercury, Lead, and Cadium perhaps.
    What about the Manhattan Project.. Did one of the leading scientist actually grab a chunk of U235 to prevent it from going critical?
    What about developers of X-rays and radiation burns?
    And heavy metal poisionings amongst metallurgist that developed new steel alloys.

    Alfred Nobel invented plywood? I didn't know that.

    I knew Bill Whelan and in the 1970s he was reputed to be Mr. Plywood for all of USA and Canada.. the leading US authority on making it. I worked for him, took care of his several homes around the Northwest. http://trove.nla.gov.au/work/51092089?q=william+whelan&c=article&versionId=64029012
  • Heater.Heater. Posts: 21,230
    edited 2013-05-09 12:35
    Curie I was not going to count as she made it to 67, but yes she was very sick for a long time as result of her experiments.
    I read a Tesla biography a while back and don't recall he went mad any more so than many of us will get dementia anyway. Have to check.
    Manhattan project, yes, there were two criticality accidents killing Louis Slotin and Harry K. Daghlian. On the whole the Manhatten guys came out of it quite well I thought.

    Perhaps this line of inquiry is a bit morbid. I should drop it.

    "Mr Plywood", what a great title.
  • NWCCTVNWCCTV Posts: 3,629
    edited 2013-05-09 17:10
    Talk about straying from the OP's question!!!!
  • ercoerco Posts: 20,256
    edited 2013-05-09 18:45
    Heater. wrote: »
    "Mr Plywood", what a great title.

    I second that! :)
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2013-05-09 20:05
    Loopy Byteloose wrote: »
    Those were the days... when inventors were found dead in their labs from either explosions, electrocution, or poisoning.

    Yes, instead these are the days when inventors are still found alive after explosions, electro-not-quite-cution, or poisoning, but fortunately only one at a time :innocent:
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