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Stepping up voltage

Discussion in 'General Electronics Discussion' started by komalbarun, May 22, 2013.

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  1. komalbarun

    komalbarun

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    Nov 25, 2011
    All i want to know is if this circuit will work? if not, then why will it not work?
     

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    Last edited: May 22, 2013
  2. BobK

    BobK

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    Jan 5, 2010
    Define "work"

    Bob
     
  3. komalbarun

    komalbarun

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    Nov 25, 2011
    sorry about that. Will it step up the voltage, assuming it is an ideal step up transformer?
     
  4. duke37

    duke37

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    Jan 9, 2011
    It should 'work' but it will depend on the component values as to what you get.

    R3 (1k) will limit the power and you may get out less than you put in.
     
  5. komalbarun

    komalbarun

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    Nov 25, 2011
    thanks :)
     
  6. BobK

    BobK

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    Jan 5, 2010
    A better circuit would use a full H-bridge. DC to AC inverter.

    Bob
     
  7. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Yes, R3 is an unrealistic value. Way to high.

    Chris
     
  8. komalbarun

    komalbarun

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    Nov 25, 2011
    what's a full H-bridge?

    and yeah R3 wans't supposed to be 1k [ there wasn't supposed to be any value there xD]
     
  9. duke37

    duke37

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    Jan 9, 2011
    You will need to specify the power supply and the components.
    Fets will be better than npn transistors if they are being driven by logic circuits since they take little power to drive. They are also more efficient.

    You can look up H-bridge yourself if you wish. It is a circuit which can change the polarity of the output, often used to reverse DC motors. It will have protection from the case where the two transistors are on for a very short time (shoot through) during switch over. Your circuit does not have this protection which may be a problem.
     
  10. komalbarun

    komalbarun

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    Nov 25, 2011
    I will look up the h bridge. Thnx for the help.
     
  11. komalbarun

    komalbarun

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    Nov 25, 2011
    shoot through = both transistors on?
    so this is a possible case?

    btw thx to have talked abt h bridge. I knw a lot more now :)
     
  12. duke37

    duke37

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    Jan 9, 2011
    Yes, shoot through is a term used where one transistor turns on before the other is fully turned off. This may not be a problem if the current is limited and it does not occur often.
    An invertor running at 100kHz with a 1microsecond overlap will have problems, one running at 10kHz with the same overlap may not have a problem.
     
  13. komalbarun

    komalbarun

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    Nov 25, 2011
    lol I understood what you said ! I surprise myself sometimes lol xD

    Thanks a lot for the help :)
     
  14. komalbarun

    komalbarun

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    Nov 25, 2011
    Won't the H-bridge have a shoot-through time too?
     
  15. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Yes and so does TTL. With high speed comes shoot-through and subsequent spikes on the supply rails. This is why good supply rail bypassing is important. On an H-Bridge it can be reduced greatly but at the expense of switching speed.

    Chris
     
  16. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    A good H Bridge driver will turn one transistor off before turning the other one on to reduce or eliminate shoot-through. It's especially an issue with mosfets.

    Actually CMOS has interesting issues with shoot-through. Sometimes these are called "crowbar currents"
     
  17. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    I imagine you're referring to a design that comprises more than your basic 2 NPN's, 2 PNP's.

    Chris
     
  18. komalbarun

    komalbarun

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    Nov 25, 2011
    yes, thanks to all of you for the help :)
     
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