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Re: [Electronics_101] what component to use to build a bridge rectifier??

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  • peter tremewen
    I m sure you have good reasons for reinventing the wheel so to speak, But I think you will find there are ready made and very cheap bridge rectifier modules
    Message 1 of 18 , Feb 29, 2004
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              I'm sure you have good reasons for reinventing the wheel so to speak,  But I think you will find there are ready made and very cheap bridge rectifier modules for just about any occasion. I would seriously recommend that you use one of these. If you really want to make a diode bridge from discrete components though, for most applications you can't beat the IN4004 or IN4008 diodes. They give fairly good cut off and voltage tolerance, plus load capability. They are cheap and fairly easy to get hold of. All a definite plus when making a general purpose power supply.
       
                      The Sinister Dragon
       
       
       
       
      ----- Original Message -----
      From: Flux
      Sent: Monday, March 01, 2004 2:46 PM
      Subject: [Electronics_101] what component to use to build a bridge rectifier??

      I know that using 4 diodes can do that

      but can anyone give an example and point out what I shoudl take care
      during the selection of the components(e.g. specification, model,
      type....)

      Thanks
    • Mario Lopez
      There is easiest alternatives to build a rectifier with a ready made modules. Hre are asy to implement, and almost you onley need to know the forward current
      Message 2 of 18 , Mar 1, 2004
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        There is easiest alternatives to build a rectifier with a ready made modules. Hre are asy to implement, and almost you onley need to know the forward current and the forward voltage.
        But if you decide to build a diode bridge, you need to know these maximun parameters:
        1. Forward current
        2. Forward voltage
        3. Reverse voltage (sometimes the same as forward voltage)
        4. Total power dispation
        In a second place, but not less important:
        5. Forward peak current
        6. Forward peak voltage
        7. Reverse peak voltage
        8. Conduction time (this paramenter is relationed with the filter and the maximun forward peak current)
        9. Max operating temperature and thermal resistance (if you need to install a heatsink)
         
        If there's any corrections, please reply¡¡
         
        PS: Sorry for my bad english...
         
         


        Flux <bene-tam@...> wrote:
        I know that using 4 diodes can do that

        but can anyone give an example and point out what I shoudl take care
        during the selection of the components(e.g. specification, model,
        type....)

        Thanks



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      • Roy J. Tellason
        ... To add to this, the price differences between different voltages of diode are very small, and I routinely use 1000V parts in stuff that I build. To shop
        Message 3 of 18 , Mar 1, 2004
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          On Sunday 29 February 2004 11:40 pm, Don Kinzer wrote:

          > As far as diode selection is concerned, the same parameters are
          > important as when you select a pre-fabricated bridge rectifier. The
          > primary parameters of interest are 1) peak inverse voltage (sometimes
          > called peak reverse voltage) and 2) average forward current. The PIV
          > should be larger than the maximum voltage that the diode will see.

          To add to this, the price differences between different voltages of diode are
          very small, and I routinely use 1000V parts in stuff that I build. To shop
          for cheaper parts only makes a lot of sense when you're buying in
          manufacturing quantities, thousands of units at a time, but not for any
          sort of hobby use.

          Also, I tend to over-spec rectifier diodes in general. A failed transformer
          will just not work -- other parts failing will have other side effects. But
          failed diodes, particularly if they short, can result in lots of other
          parts going bad too...
        • Phil
          ... for any ... I agree but several of the surplus places (gold mine, alltronics,...) regularly have specials on 1n400x. I picked up 40 1N4004 for a buck a
          Message 4 of 18 , Mar 1, 2004
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            --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
            <rtellason@b...> wrote:
            > To shop
            > for cheaper parts only makes a lot of sense when you're buying in
            > manufacturing quantities, thousands of units at a time, but not
            for any
            > sort of hobby use.
            >

            I agree but several of the surplus places (gold mine, alltronics,...)
            regularly have specials on 1n400x. I picked up 40 1N4004 for a buck
            a while back. At those prices its worth it to stock up. though I
            think you can get them from digikey for like $.04 in small lots.
            pretty minimal cost. I use them in lots of ways.
          • dangermouse
            I m not sure if anyone has mentioned this yet, so sorry if I m just repeating. Just be sure that you understand what PEAK inverse voltage means. This refers
            Message 5 of 18 , Mar 1, 2004
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              I'm not sure if anyone has mentioned this yet, so sorry if I'm just repeating.
               
              Just be sure that you understand what PEAK inverse voltage means.  This refers to the peak instantaneous value of the AC voltages that you expect the diode to see.  If you expect the highest voltage to be 120VAC RMS, for example, the peak voltage will be about 170V, or RMS voltage x (sqrt(2)), and your diodes must be sized to handle that.
               
              Of course, if you follow Peter's advice, which I most certainly do (they're cheap and much less likely to fail from some unanticipated transient), your 1N4008 diode won't much care whether you give it 120V or 170V, as it's rated for 1000V!
               
              The same goes for pre-manufactured bridge rectifier modules, by the way--it's higher current capacity that really costs more.  Higher PIV hardly increases costs at all, and it's great insurance.
               
              -DM
              ----- Original Message -----
              Sent: Monday, March 01, 2004 12:09 AM
              Subject: Re: [Electronics_101] what component to use to build a bridge rectifier??

                      I'm sure you have good reasons for reinventing the wheel so to speak,  But I think you will find there are ready made and very cheap bridge rectifier modules for just about any occasion. I would seriously recommend that you use one of these. If you really want to make a diode bridge from discrete components though, for most applications you can't beat the IN4004 or IN4008 diodes. They give fairly good cut off and voltage tolerance, plus load capability. They are cheap and fairly easy to get hold of. All a definite plus when making a general purpose power supply.
               
                              The Sinister Dragon
               
               
               
               
              ----- Original Message -----
              From: Flux
              Sent: Monday, March 01, 2004 2:46 PM
              Subject: [Electronics_101] what component to use to build a bridge rectifier??

              I know that using 4 diodes can do that

              but can anyone give an example and point out what I shoudl take care
              during the selection of the components(e.g. specification, model,
              type....)

              Thanks
            • Roy J. Tellason
              ... Not a bad deal, that one. And a 400V part is likely to cover most of what we re doing with electronics these days, the higher voltages were only
              Message 6 of 18 , Mar 1, 2004
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                On Monday 01 March 2004 12:19 pm, Phil wrote:
                > --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
                >
                > <rtellason@b...> wrote:
                > > To shop
                > > for cheaper parts only makes a lot of sense when you're buying in
                > > manufacturing quantities, thousands of units at a time, but not
                > > for any sort of hobby use.

                > I agree but several of the surplus places (gold mine, alltronics,...)
                > regularly have specials on 1n400x. I picked up 40 1N4004 for a buck
                > a while back. At those prices its worth it to stock up. though I
                > think you can get them from digikey for like $.04 in small lots.
                > pretty minimal cost. I use them in lots of ways.

                Not a bad deal, that one. And a 400V part is likely to cover most of what
                we're doing with electronics these days, the higher voltages were only
                something I'd use for tube stuff way back when. There was a *real* common
                part that was sold under a bunch of different numbers and which had a rating
                of 1000V and 2.5A, I used to buy bags of 25 of them, though I don't think
                I ever quite finished using the last bag completely.

                One guy I was talking to a while back said that he didn't even bother to
                salvage 1N4001s, but I still see them as being useful, for places like
                across a relay coil or similar inductive load, where you don't really care
                what the reverse voltage is as it's never going to see all that much.
              • Roy J. Tellason
                ... Good point, and it s not just the peak AC voltage, but the peak instantaneous value of the AC voltage applied to one side _and_ whatever the capacitor
                Message 7 of 18 , Mar 1, 2004
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                  On Monday 01 March 2004 12:21 pm, dangermouse wrote:
                  > I'm not sure if anyone has mentioned this yet, so sorry if I'm just
                  > repeating.
                  >
                  > Just be sure that you understand what PEAK inverse voltage means. This
                  > refers to the peak instantaneous value of the AC voltages that you expect
                  > the diode to see. If you expect the highest voltage to be 120VAC RMS, for
                  > example, the peak voltage will be about 170V, or RMS voltage x (sqrt(2)),
                  > and your diodes must be sized to handle that.

                  Good point, and it's not just the peak AC voltage, but the peak
                  instantaneous value of the AC voltage applied to one side _and_ whatever the
                  capacitor that's typically connected to the other side, which under no or
                  small load will be just as high. So for 120VAC your cap will charge up to
                  170V or so, and then when the polarity of the applied AC reversed the
                  cathode of the diode will be at +170, while the anode can reach -170,
                  giving a total of 340V across the diode. Some may choose 400V parts but I'd
                  feel more comfortable going higher.

                  > Of course, if you follow Peter's advice, which I most certainly do (they're
                  > cheap and much less likely to fail from some unanticipated transient), your
                  > 1N4008 diode won't much care whether you give it 120V or 170V, as it's
                  > rated for 1000V!

                  1N4008? My chart only goes up to 1N4007, which is shown as a 1000V part.
                • dangermouse
                  Perhaps that s true for consumer-type work, but in industrial environments, which are notoriously nasty (chemically, thermally and electrically) that 1000V PIV
                  Message 8 of 18 , Mar 1, 2004
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                    Perhaps that's true for consumer-type work, but in industrial environments,
                    which are notoriously nasty (chemically, thermally and electrically) that
                    1000V PIV is wonderful for preventing failures due to the guy down the hall
                    starting and stopping his welder and other such stuff.

                    -DM

                    ----- Original Message -----
                    From: "Roy J. Tellason" <rtellason@...>
                    To: <Electronics_101@yahoogroups.com>
                    Sent: Monday, March 01, 2004 2:35 PM
                    Subject: Re: [Electronics_101] Re: what component to use to build a bridge
                    rectifier??


                    > On Monday 01 March 2004 12:19 pm, Phil wrote:
                    > > --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
                    > >
                    > > <rtellason@b...> wrote:
                    > > > To shop
                    > > > for cheaper parts only makes a lot of sense when you're buying in
                    > > > manufacturing quantities, thousands of units at a time, but not
                    > > > for any sort of hobby use.
                    >
                    > > I agree but several of the surplus places (gold mine, alltronics,...)
                    > > regularly have specials on 1n400x. I picked up 40 1N4004 for a buck
                    > > a while back. At those prices its worth it to stock up. though I
                    > > think you can get them from digikey for like $.04 in small lots.
                    > > pretty minimal cost. I use them in lots of ways.
                    >
                    > Not a bad deal, that one. And a 400V part is likely to cover most of
                    what
                    > we're doing with electronics these days, the higher voltages were only
                    > something I'd use for tube stuff way back when. There was a *real* common
                    > part that was sold under a bunch of different numbers and which had a
                    rating
                    > of 1000V and 2.5A, I used to buy bags of 25 of them, though I don't
                    think
                    > I ever quite finished using the last bag completely.
                    >
                    > One guy I was talking to a while back said that he didn't even bother to
                    > salvage 1N4001s, but I still see them as being useful, for places like
                    > across a relay coil or similar inductive load, where you don't really
                    care
                    > what the reverse voltage is as it's never going to see all that much.
                    >
                    >
                    >
                    >
                    >
                    > Yahoo! Groups Links
                    >
                    >
                    >
                    >
                    >
                  • dangermouse
                    You re right, it s 1N4007. When Peter said 4008, I just parroted him rather than check it for myself. See? It s someone else s fault. I never make misteaks
                    Message 9 of 18 , Mar 1, 2004
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                      You're right, it's 1N4007. When Peter said 4008, I just parroted him rather
                      than check it for myself.

                      See? It's someone else's fault. I never make misteaks myself...

                      -DM

                      ----- Original Message -----
                      From: "Roy J. Tellason" <rtellason@...>
                      To: <Electronics_101@yahoogroups.com>
                      Sent: Monday, March 01, 2004 2:39 PM
                      Subject: Re: [Electronics_101] what component to use to build a bridge
                      rectifier??


                      > On Monday 01 March 2004 12:21 pm, dangermouse wrote:
                      > > I'm not sure if anyone has mentioned this yet, so sorry if I'm just
                      > > repeating.
                      > >
                      > > Just be sure that you understand what PEAK inverse voltage means. This
                      > > refers to the peak instantaneous value of the AC voltages that you
                      expect
                      > > the diode to see. If you expect the highest voltage to be 120VAC RMS,
                      for
                      > > example, the peak voltage will be about 170V, or RMS voltage x
                      (sqrt(2)),
                      > > and your diodes must be sized to handle that.
                      >
                      > Good point, and it's not just the peak AC voltage, but the peak
                      > instantaneous value of the AC voltage applied to one side _and_ whatever
                      the
                      > capacitor that's typically connected to the other side, which under no or
                      > small load will be just as high. So for 120VAC your cap will charge up to
                      > 170V or so, and then when the polarity of the applied AC reversed the
                      > cathode of the diode will be at +170, while the anode can reach -170,
                      > giving a total of 340V across the diode. Some may choose 400V parts but
                      I'd
                      > feel more comfortable going higher.
                      >
                      > > Of course, if you follow Peter's advice, which I most certainly do
                      (they're
                      > > cheap and much less likely to fail from some unanticipated transient),
                      your
                      > > 1N4008 diode won't much care whether you give it 120V or 170V, as it's
                      > > rated for 1000V!
                      >
                      > 1N4008? My chart only goes up to 1N4007, which is shown as a 1000V part.
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      > Yahoo! Groups Links
                      >
                      >
                      >
                      >
                      >
                    • Roy J. Tellason
                      ... Oh sure, if I m gonna buy some I ll probably just go ahead and get the 1000V parts, the price difference just isn t worth it... Though if the industrial
                      Message 10 of 18 , Mar 1, 2004
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                        On Monday 01 March 2004 02:41 pm, dangermouse wrote:
                        > Perhaps that's true for consumer-type work, but in industrial environments,
                        > which are notoriously nasty (chemically, thermally and electrically) that
                        > 1000V PIV is wonderful for preventing failures due to the guy down the hall
                        > starting and stopping his welder and other such stuff.

                        Oh sure, if I'm gonna buy some I'll probably just go ahead and get the 1000V
                        parts, the price difference just isn't worth it...

                        Though if the industrial environment in question is *that* nasty then maybe
                        surge protection is in order, before it gets to the rectifiers...
                      • dangermouse
                        ... From: Roy J. Tellason To: Sent: Monday, March 01, 2004 3:41 PM Subject: Re: [Electronics_101]
                        Message 11 of 18 , Mar 1, 2004
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                          ----- Original Message -----
                          From: "Roy J. Tellason" <rtellason@...>
                          To: <Electronics_101@yahoogroups.com>
                          Sent: Monday, March 01, 2004 3:41 PM
                          Subject: Re: [Electronics_101] Re: what component to use to build a bridge
                          rectifier??


                          > Though if the industrial environment in question is *that* nasty then
                          maybe
                          > surge protection is in order, before it gets to the rectifiers...

                          I had to re-compose myself for a few minutes after reading that comment.
                          Not because you aren't right, but because you are, and other things...

                          Of COURSE surge protection, and a gazillion other things besides, are in
                          order. But in most industrial environments, cost reduction is king, and the
                          bean counters in the front office get to say which costs get "reducted" and
                          which don't.

                          In other words, that's why we sub a few .10 1N4007s into circuits, and have
                          quit trying (except for a few notable cases) to sell large-scale protection
                          to most industrial clients. They just aren't interested.

                          -DM
                        • peter tremewen
                          The problem with the cost reduction is king approach I have always found, is that when it eventually does fail, you are the one who wears the blame for the
                          Message 12 of 18 , Mar 1, 2004
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                                    The problem with the "cost reduction is king" approach I have always found, is that when it eventually does fail,  you are the one who wears the blame for the fault. Clients don't wont to know that it broke down cause they didn't want to pay a few extra dollars for surge protection. Whenever a client comes up to me and says "I can get it cheaper down at blah, Blah" I simply tell them that I sell middle of the range equipment and that the slight extra expense is worth it when you consider the cost of  break down. I consider the few clients I loose because of this are just not worth the trouble they will cause latter......  When I am asked to do so, I have a reputation for producing reasonable quality reliable equipment.....   Most people, especially those who I have previously dealt with,  are willing to pay just a little bit more for that I have found......
                             
                                            The Sinister Dragon
                             
                            Of COURSE surge protection, and a gazillion other things besides, are in
                            order.  But in most industrial environments, cost reduction is king, and the
                            bean counters in the front office get to say which costs get "reducted" and
                            which don't.

                            In other words, that's why we sub a few .10 1N4007s into circuits, and have
                            quit trying (except for a few notable cases) to sell large-scale protection
                            to most industrial clients.  They just aren't interested.

                            -DM

                          • James Liddle
                            In a previous life, before Disney & before downsizing, I was a video systems designer for ABC. We had a saying that There s never enough money to do it
                            Message 13 of 18 , Mar 2, 2004
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                              In a previous life, before Disney & before downsizing,
                              I was a video systems designer for ABC. We had a
                              saying that "There's never enough money to do it
                              right, but there's always enough money to fix it
                              later". Eventually the system (control room, intercom
                              system, truck) worked properly, but it was
                              frustrating. Now however, with outsourcing produced
                              projects, you'd better get it right the first time,
                              because that's the way it's going to be. The cost is
                              lower, but so is the usability & reliability.



                              --- peter tremewen <Ptremewe@...> wrote:
                              > The problem with the "cost reduction is
                              > king" approach I have always found, is that when it
                              > eventually does fail, you are the one who wears the
                              > blame for the fault. Clients don't wont to know that
                              > it broke down cause they didn't want to pay a few
                              > extra dollars for surge protection. Whenever a
                              > client comes up to me and says "I can get it cheaper
                              > down at blah, Blah" I simply tell them that I sell
                              > middle of the range equipment and that the slight
                              > extra expense is worth it when you consider the cost
                              > of break down. I consider the few clients I loose
                              > because of this are just not worth the trouble they
                              > will cause latter...... When I am asked to do so, I
                              > have a reputation for producing reasonable quality
                              > reliable equipment..... Most people, especially
                              > those who I have previously dealt with, are willing
                              > to pay just a little bit more for that I have
                              > found......
                              >
                              > The Sinister Dragon
                              >
                              > Of COURSE surge protection, and a gazillion other
                              > things besides, are in
                              > order. But in most industrial environments, cost
                              > reduction is king, and the
                              > bean counters in the front office get to say which
                              > costs get "reducted" and
                              > which don't.
                              >
                              > In other words, that's why we sub a few .10
                              > 1N4007s into circuits, and have
                              > quit trying (except for a few notable cases) to
                              > sell large-scale protection
                              > to most industrial clients. They just aren't
                              > interested.
                              >
                              > -DM
                              >
                              >
                              >

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                            • manifold
                              ... For general rectification of up to an Amp, with no special requirements, I also use the 1n400x family. I have some generic 3A diodes in a power supply and
                              Message 14 of 18 , Mar 2, 2004
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                                --- In Electronics_101@yahoogroups.com, "Flux" <bene-tam@d...> wrote:
                                > I know that using 4 diodes can do that
                                >
                                > but can anyone give an example and point out what I shoudl take care
                                > during the selection of the components(e.g. specification, model,
                                > type....)
                                >
                                > Thanks

                                For general rectification of up to an Amp, with no special
                                requirements, I also use the 1n400x family. I have some generic 3A
                                diodes in a power supply and a 25A, 50PIV bridge module in another
                                power supply.

                                There are special cases where special diode selection is important.
                                For example, if you are rectifying very low voltages, you may want to
                                use low forward voltage diodes like Schottky diodes. There are also
                                alternative devices for noise reduction. Yes, a standard rectifier can
                                generate enough noise to keep a device from passing FCC requirements.

                                These alternatives are more expensive than either regular diodes in a
                                bridge circuit, or bridge modules.
                              • Roy J. Tellason
                                ... Now here we differ. Those parts are rated at 1A as an absolute maximum rating , and I surely wouldn t use them for up to an amp , maybe use them in
                                Message 15 of 18 , Mar 3, 2004
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                                  On Wednesday 03 March 2004 12:01 am, manifold wrote:
                                  > --- In Electronics_101@yahoogroups.com, "Flux" <bene-tam@d...> wrote:
                                  > > I know that using 4 diodes can do that
                                  > >
                                  > > but can anyone give an example and point out what I shoudl take care
                                  > > during the selection of the components(e.g. specification, model,
                                  > > type....)
                                  > >
                                  > > Thanks
                                  >
                                  > For general rectification of up to an Amp, with no special
                                  > requirements, I also use the 1n400x family.

                                  Now here we differ. Those parts are rated at 1A as an "absolute maximum
                                  rating", and I surely wouldn't use them for "up to an amp", maybe use them
                                  in stuff that would go to half or three-quarters of an amp at most. You
                                  really do need to leave some safety margin there.

                                  > I have some generic 3A diodes in a power supply and a 25A, 50PIV bridge
                                  > module in another power supply.

                                  For a power supply that might go "up to an amp" I'd be using the 3A parts.

                                  > There are special cases where special diode selection is important.
                                  > For example, if you are rectifying very low voltages, you may want to
                                  > use low forward voltage diodes like Schottky diodes.

                                  Or fairly high currents. The lower voltage drop means they run cooler, and
                                  are therefore more efficient. Which means less heat. They're commonly used
                                  in computer power supplies, among other places.
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