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Thread: can i get 5v 2W at the output if the 7805s are rated at 1W each

  1. #1
    Constant Bitrate minghi's Avatar
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    can i get 5v 2W at the output if the 7805s are rated at 1W each

    the title says it all
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  2. #2
    FLAC Chairboy's Avatar
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    You mean amp, not watt, right?

    ...and no, one will be overloaded first, followed by the next.
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  3. #3
    Constant Bitrate minghi's Avatar
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    you are right, AMP
    damm that vodka.....

    or what is the best way to get more than 1A, say 5A and 5v at the output
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    128MB RAM-$10
    6GB+80GB 2.5" HDDs-$130
    GPS-$60
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    10" pioneer 500w sub-$55
    sony xm-3020 30W amp-$10
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  4. #4
    FLAC Chairboy's Avatar
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    There are some 2 amp versions of the 7805 with mega heatsinks, don't remember the letter modifer at the end.

    Additionally, MAXIM IC has some nice voltage regulators that'll do it, but they're not as easy to find. You'd have to buy them online.

    Your best bet... might be to find a car adapter for something that takes 5v at greater then 2 amps and just scavenge the regulator circuit from it?
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  5. #5
    Raw Wave shotgunefx's Avatar
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    You could use something like a
    LM323K. That will supply 3 amps. It's a big TO-3 package.

  6. #6
    Constant Bitrate minghi's Avatar
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    Quote Originally Posted by shotgunefx
    You could use something like a
    LM323K. That will supply 3 amps. It's a big TO-3 package.


    very nice, thanks,

    now, am i looking at a 12V 3A regulator here http://www.mouser.com/index.cfm?hand..._pcodeid=51238 i am looking for a 12v version too
    400W Power Amplifier -$25
    P3 laptop mobo-$30ish
    128MB RAM-$10
    6GB+80GB 2.5" HDDs-$130
    GPS-$60
    7" TS Lilliput-$280
    10" pioneer 500w sub-$55
    sony xm-3020 30W amp-$10
    jensen 340W A34XP amp-$40
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  7. #7
    Constant Bitrate minghi's Avatar
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    nevermind

    found this http://www.mouser.com/index.cfm?hand..._pcodeid=51138

    thanks a lotttt
    400W Power Amplifier -$25
    P3 laptop mobo-$30ish
    128MB RAM-$10
    6GB+80GB 2.5" HDDs-$130
    GPS-$60
    7" TS Lilliput-$280
    10" pioneer 500w sub-$55
    sony xm-3020 30W amp-$10
    jensen 340W A34XP amp-$40
    mp3car.com resources and members- priceless

  8. #8
    What can I say? I like serial. Curiosity's Avatar
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    Switchers will cause you much less problems in the end, but cost more.

  9. #9
    Low Bitrate Mcnovy's Avatar
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    hmm minghi

    are you trying to make yourself a computer PSU..?

    things you should be aware of..!

    1. 12 volt serie regulators needs a volt drop at about 1 volt.
    so you got to have at least 13 volt's, you do when you car and altennator is running, but as soon as you turn you car of, you will be having some problems maintaining the Voltage.
    2. 5 volt serieregulators.
    well the drop voltage will be no problem at all, BUT
    remember, the current pulled ´from output, will also be the current in the input.
    cons.
    1. Heat, you'll have som great heat problems.
    eksplanation.
    1 amp at output, and 5 volt = 5 watt
    Current output = current input
    ex
    1 amp output, then the current from the batteri will be 1 amp, you output is 5 volt, and you input is 12 volt.
    thats again, 5 V * 1 Amp = 5 watt
    12 V * 1 Amp = 12 Watt
    and that would make the wattage over the regulator 7 watt, and that is a little hot.
    the regulator would have effieciency at about 42 %, and 48 % loss, well, i would'nt recommend it, hope i made a point.

    Good Luck
    Sorry for the english

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  10. #10
    Constant Bitrate minghi's Avatar
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    Quote Originally Posted by Mcnovy
    hmm minghi

    are you trying to make yourself a computer PSU..?

    things you should be aware of..!

    1. 12 volt serie regulators needs a volt drop at about 1 volt.
    so you got to have at least 13 volt's, you do when you car and altennator is running, but as soon as you turn you car of, you will be having some problems maintaining the Voltage.
    2. 5 volt serieregulators.
    well the drop voltage will be no problem at all, BUT
    remember, the current pulled ´from output, will also be the current in the input.
    cons.
    1. Heat, you'll have som great heat problems.
    eksplanation.
    1 amp at output, and 5 volt = 5 watt
    Current output = current input
    ex
    1 amp output, then the current from the batteri will be 1 amp, you output is 5 volt, and you input is 12 volt.
    thats again, 5 V * 1 Amp = 5 watt
    12 V * 1 Amp = 12 Watt
    and that would make the wattage over the regulator 7 watt, and that is a little hot.
    the regulator would have effieciency at about 42 %, and 48 % loss, well, i would'nt recommend it, hope i made a point.

    Good Luck


    hmmm...nice

    actually, i am trying to power a usb hub, external hard drive and couple other stuff with this
    400W Power Amplifier -$25
    P3 laptop mobo-$30ish
    128MB RAM-$10
    6GB+80GB 2.5" HDDs-$130
    GPS-$60
    7" TS Lilliput-$280
    10" pioneer 500w sub-$55
    sony xm-3020 30W amp-$10
    jensen 340W A34XP amp-$40
    mp3car.com resources and members- priceless

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