12V DC to 120V AC IMPORTANT!!

Discussion in 'The Projects Forum' started by badrove, Apr 4, 2008.

  1. badrove

    Thread Starter Member

    Mar 18, 2008
    12
    0
    Hello,

    I am loking for a circuitry to generate an alternatif signal (about 120 volts AC) but i have just a 12VDC alimentation.

    the output frequency should be 100KHz.

    Thanks for you
     
  2. vel

    New Member

    Apr 4, 2008
    3
    0
    pls give circuit
     
  3. Søren

    Senior Member

    Sep 2, 2006
    472
    28
    Hi,

    Usually I have this effect on women only ;)


    Please don't mark your post with "IMPORTANT", that only makes people NOT wanna answer. Any post is important to one who needs an answer, but not really very important to the ones able to give the answer.

    Personally, I have a tendency to filter out such posts as well, but a quick answer would be: "Hook up a 555 to a ferrite transformer wound for the purpose".

    (See, even unintentional flattery gets you somewhere ;))
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Are you trying to make an inverter to drive a load, or do you simply need a circuit for demonstration?
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
  6. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    Here is how I would do it...

    [​IMG]

    I have never built this circuit. There may be traps or problems I haven't anticipated, which is why prototypes are built.

    Unless we are talking a light load, the transistors will need heat sinked. This circuit should put out a substantial amount of current, so normal safety precautions should be take for high voltages.
     
  7. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    You're going to have a hard time making a 100KHz 120Vac signal with any sort of power capability. What output power or current do you need?

    Steve
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Interesting circuit, Bill.

    Just one thing - I recently was reading about a circuit similar to yours; a fellow tried to make the circuit more simple by eliminating the base resistors from the transistors forming the H-bridge; it didn't work after that.
    [eta] Found the link to that similar circuit: http://www.solarbotics.net/library/circuits/driver_4varHbridge.html

    A wild guess (actually, 12v/100mA, half of the current capacity of a bipolar 555) tells me that a minimum of 120 Ohms is needed on the base of each transistor.
     
  9. badrove

    Thread Starter Member

    Mar 18, 2008
    12
    0
    hi,

    i need a low current, about 20mA or less

    badrove
     
  10. DC_Kid

    Distinguished Member

    Feb 25, 2008
    638
    9
    are you sure 100kHz? why 100kHz? stun gun? what is it for?
     
  11. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535

    There is one big difference between circuits, the one I drew is an emitter follower design, no resistors needed.
     
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