Whats the difference? (besides looking different?)
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Re: Bridge rectifier vs four diodes
The 4-diode treatment as it is known is generally used because 4 discrete diodes are cheaper. However this almost always indicates a very low quality supply, because they use low current diodes. (4A if you're lucky, most use 2-3A diodes, or even a mixture of the two!).
If you're running 220v mains this isn't a problem (220x2 = 440W, with 75% efficiency you get 330W, more than a low-end power supply can deliver anyway), however in the US you have 110v mains, and 2 amp diodes would be limiting your supply to a silly output power of 165 watts. If you have 5-amp diodes on hand for example, there is nothing wrong in keeping the 4-diode configuration and simply replacing the 2-amp ones with 5-amp ones. Some power supplies don't even have room for a bridge rectifier so this can be the only solution.A working TV? How boring!Originally posted by PeteS in CA -
Re: Bridge rectifier vs four diodes
I live in the us. 120v. So that basically means that like 5 of my psus are <200w? Can i put in abridge recitifer?Comment
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Re: Bridge rectifier vs four diodes
Some psu manufacturers place the 4 diodes vertically so they get some cooling from the fan:
Placing them in parallel with pcb is completely stupid...
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Re: Bridge rectifier vs four diodes
As Th3_uN1Qu3 said, generally the cheaper PSU's use diodes.
That isn't an absolute indicator of quality though. - Just the usual case.
It doesn't really matter if they use a rectifier IC or diodes.
It's a rectifier either way.
All that matters is how much current it can handle.
.Mann-Made Global Warming.
- We should be more concerned about the Intellectual Climate.
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Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
- Dr Seuss
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You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
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Re: Bridge rectifier vs four diodes
Howdo i tell The diode current rating?Comment
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Re: Bridge rectifier vs four diodes
Usually you can estimate based on the size (i.e. small = low current, big = high current). You can also look at the numbers on them (which may require unsoldering them from the board) and try to find a datasheet.Comment
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Re: Bridge rectifier vs four diodes
Whqt do i compare them to sizewise?Comment
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Re: Bridge rectifier vs four diodes
Best is just to look up the models printed on them and read the datasheet... But judging by package size, the small ones like in the last 2 pics don't take more than 2A, the larger ones (first two pics) are 3 to 5A.A working TV? How boring!Originally posted by PeteS in CAComment
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Re: Bridge rectifier vs four diodes
The diodes of the first pic are 1N5406 3A.
Note also that the first 2 psus have somehow decent transient filter, while the other 2 with the tiny diodes lack most of the components.Comment
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Re: Bridge rectifier vs four diodes
i believe that theres got to be a significant difference, but if you ask me, theres none, just design, space, cost, quality, power use and relief, i dont know (probably those are significant when u produce the units by thousands)... i mean, u can check functionality same way in both so i guess down to operation is the same.
but this is just me............ and guessing
peace.We don't have a great war in our generation, or a great depression, but we do, we have a great war of the spirit. We have a great revolution against the culture. The great depression is our lives. We have a spiritual depression.Comment
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Re: Bridge rectifier vs four diodes
My guess is that it's cheaper to -buy- diodes but it's cheaper and faster to -install- the IC Rectifiers.
Some poor little Asian girl had to fiddle around bending leads on the diodes.
- Cheaper to buy but more work to put in.Mann-Made Global Warming.
- We should be more concerned about the Intellectual Climate.
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Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
- Dr Seuss
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You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
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Hi all, a newby question about a bridge rectifier I'm trying to identify.
I'm in the midst of reparing a battery charger in work which went pop, The bridge rectifier has shorted and took out a couple of other components. The rectifier in question has a part number KPB305G, and it looks like it's obsolete. Does any one know what I could replace it with?... -
Dear members,
I have a linear variable power supply with unknown brand name that I used for voltage injection.
Then it failed. I discovered that its transistors (Q1 and Q2) are shorted.
In addition, I discovered that its zener diodes are defective.
I can replace the burned transistors.
But I do not know the model of the zener diodes. the model number is not marked on the zener diodes.
Therefore, I cannot replace the zener diodes.
I do not want to test the zener diodes in a test circuit to discover their model or value.
no schematics are available... -
Hello
My Fujitsu Esprimo Q556 motherboards blew up. At least fuse, bridge rectifier and capacitor got damaged. I have changed fuse and bridge rectifier (DF1508S), but I don't know what capacitor it is (picture). I know that capacitors size is 47nF, but I don't know other specs for it. Can you help me to choose right capacitor for my motherboard?
There is 240V AC on input side of bridge rectifier and 340V DC as output on capasitors side.
Thanks.... -
I have a 40 volt AC transformer that I put a bridge rectifier on, and I wanted to see the input signal and the output signal on the same screen on my scope, so I set one channel up with the test lead on one side of the input and the ground lead on the other side of the input, then I used another channel on the scope and clipped the test lead on the positive side of the output then the ground on the negative side of the output.
When I connected the transformer to power, the wire that was connected between the ground lead on the second channel and the negative side of the bridge rectifier... -
Hi,
I'm learning about motherboard repair and I believe I've traced the issue down for the South Bridge on the particular motherboard I'm working on. My path of concluding that:
- There's no sign of any attempt to power on when pushing the power button.
- No PSON signal is reaching the 24-pin ATX connector.
- The Super IO chip is receiving the PS_SWITCH signal from the power button and is relaying this signal back to the South Bridge.
- The Super IO is not receiving the S_SLPS#_R signal back from the South Bridge
- If I pull the Super IO S_SLPS#_R pin...
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