How to convert 12V 1.0 A DC to 3V DC

Discussion in 'General Electronics Chat' started by beingsallu, Jul 14, 2012.

  1. beingsallu

    Thread Starter New Member

    Jul 10, 2012
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    hello every one

    I want to convert 12V 1.0 A DC to 3V DC
    is that possible if yes . so please tell me
     
  2. #12

    Expert

    Nov 30, 2010
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    It is possible. You can use a voltage regulator or a DC to DC converter.
     
  3. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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  4. wmodavis

    Well-Known Member

    Oct 23, 2010
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    It definitely possible, in fact that sort of thing is routinely done all the time.
    Voltage divider, zener diode, voltage regulator,
     
    Last edited: Jul 14, 2012
  5. takao21203

    Distinguished Member

    Apr 28, 2012
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  6. ravishankar kv

    New Member

    Jul 14, 2012
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    if output current required is less than 1A then try 7803. better use a heat sink along with that.
     
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  7. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    You can get a free finished design for this from National Semiconductor. Use their Simple Switcher software. Schematic, parts list, the whole banana. No heatsink required. part number LM2575-ADJ will work for it.
     
  8. crutschow

    Expert

    Mar 14, 2008
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    A linear regulator is simple and will give an output current of 1A maximum @ 3V with a loss in the regulator of about 9W.

    A switching regulator is more complex but can give an output over 3A maximum @ 3V with a loss in the regulator of a couple watts or less (depending upon the switching regulator used).
     
  9. beingsallu

    Thread Starter New Member

    Jul 10, 2012
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    can you tell me circuit schematic of 7803
     
  10. #12

    Expert

    Nov 30, 2010
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    There is no such thing as an LM7803. Use this.
     
  11. takao21203

    Distinguished Member

    Apr 28, 2012
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    I'd be curious to understand what is so complex about 4 components. Which I never calculate in any kind.
     
  12. #12

    Expert

    Nov 30, 2010
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    Nice photo. Do you have a schematic of this 4 component switching regulator?
     
  13. takao21203

    Distinguished Member

    Apr 28, 2012
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    Yes. Also LED is added to output + 1K resistor.

    Timing capacitor can have different values,
    I have measured lowest input current with 68pF.

    50pF, 180pF, 470pF etc., all ceramic caps.

    If you use electronic transformer, input cap. is not strictly neccessary!
     
  14. #12

    Expert

    Nov 30, 2010
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    I think I just became a fan of the simple switchers.
    I wonder if they can be purchased in New Delhi.
     
  15. tpny

    Member

    May 6, 2012
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    I would think it depends on what u will be using the 3V for.. When I needed a voltage source to drive two 3.3V ICs, I used an encapsulated DC-to-DC converter (eg, Mean Well DKA15A-05) to step 12V down to 5 then an LM1117. You can also get one to step 12V down to 3.3 in one step. (I needed 5V and 3.3V on the same board.) I'm not sure: could I have done the same with an MC33063/4 like above?..
     
  16. beingsallu

    Thread Starter New Member

    Jul 10, 2012
    18
    0
    with using LM317
    R1-220 ohm
    R2-470 ohm
    output-3.92v
    .
    is capactiors are must for this
    if yes tell me which one ?
     
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