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the circuit not working

Discussion in 'General Electronics Discussion' started by walid.anjum, Dec 25, 2013.

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  1. walid.anjum

    walid.anjum

    26
    0
    Dec 18, 2013
    the circuit attched with this message is not working properly so any help from u guys be appreciated
    values for the compnents are
    supply 15v
    r1 and r2 =250ohm 1 watt
    d1 and d2 = 1n5819
    nchannel mosfet Q1 and Q2 = irfz44
    capictor= 0.47micro farad
    L1= 1.1 micro H
    L2=2.2=nano H
     

    Attached Files:

  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,411
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    Jan 21, 2010
    the image is too small to make out. Can you post a larger one.

    It would also help if you described both what it's supposed to do and what it's doing.
     
  3. walid.anjum

    walid.anjum

    26
    0
    Dec 18, 2013
    its an induction heating ckt...i am not able to adjust the size of pic as upload lsize limit is 19.7 kb so it is makng an issue
     
  4. davenn

    davenn Moderator

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    Sep 5, 2009
    the upload size limit is ~ 100kb much more than the 19kb you said

    regardless of that a much larger gif image is only a few kb any way
    do a 600 x 400 gif of your circuit

    Dave
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    That's 97.7k -- save it as a png using paintbrush or similar.

    We routinely upload much larger images without a problem.

    If you can't do that, upload it to an image hosting site and post a link.
     
  6. walid.anjum

    walid.anjum

    26
    0
    Dec 18, 2013
    chk this circuit plz
     

    Attached Files:

  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    OK, now we have a circuit large enough to read and a description of what it's supposed to do, what is it doing (or not doing)?
     
  8. jpanhalt

    jpanhalt

    426
    4
    Nov 12, 2013
    Here is a link to the actual project: http://www.rmcybernetics.com/projects/DIY_Devices/diy-induction-heater.htm

    There are a lot of comments over about 2 years, and it seems the circuit can be made to work.

    First, I second the request to describe what it is and/or isn't doing.

    Second, please attach pictures of your project. There is some leeway in construction, but apparently not much.

    Third, Did you use exactly the components specified in the original article? If not, what substitutions did you make?

    John
     
  9. walid.anjum

    walid.anjum

    26
    0
    Dec 18, 2013
    r1 and r2 =250ohm 1 watt
    d1 and d2 = 1n5819
    nchannel mosfet Q1 and Q2 = irfz44
    capictor= 0.47micro farad
    L1= 1.1 micro H
    L2=2.2=nano H

    this is an induction heating circuit .and the compenents and their spec are given above .the main problem is that its is not generating freq at the output.is thre any simulator which can use to simulate the oscilloscope and giving graph in hertz.thanks
     
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    I believe they say that L2 should be in the region of 1mH, not 1nH -- it needs to be about a million times larger in inductance.

    What are the specs for your power supply? What current are you measuring?

    What is C1. Is it a single capacitor? They recommend several in parallel to allow for the peak current.

    Is anything getting hot?
     
  11. walid.anjum

    walid.anjum

    26
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    Dec 18, 2013
    i am using 0.47microF c1.........its 15v and 1mA current..
     
  12. jpanhalt

    jpanhalt

    426
    4
    Nov 12, 2013
    At most, that is 15 mW of power.

    What are you trying to heat? I hope its mass is appropriately small. ;) At a ratio of 15W/g, consider that one milligram of air is a little less than 1 mL. The same mass of water is 1 µL.

    John
     
    Last edited: Dec 27, 2013
  13. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,411
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    Jan 21, 2010
    If it's drawing that little current then I would assume one of the following:

    1) you've wired up the mosfets incorrectly.
    2) you've killed the mosfets in a way other than internally shorting them.

    What is your power supply? (what are its ratings -- maximum current would be a good start).

    Can you post a picture of your construction?
     
  14. jpanhalt

    jpanhalt

    426
    4
    Nov 12, 2013
    And it is almost certainly not oscillating.

    Can you (walid.anjum) measure and tell us the gate-to-ground and the drain-to-ground voltages across each mosfet?

    Please confirm the part number of the mosfets you used.

    John
     
  15. walid.anjum

    walid.anjum

    26
    0
    Dec 18, 2013
    its 3.1 volt gate to ground...and 2.84V drain to ground..........and Mosfet model num: IRZ44
     
  16. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,411
    2,779
    Jan 21, 2010
    walid.anjum, you need to read all the replies.

    The one telling you that one of your inductors is a million times too small is probably worth heeding.
     
  17. jpanhalt

    jpanhalt

    426
    4
    Nov 12, 2013
    IRZ44 is not a mosfet!

    Capture.PNG

    Do you mean IRFZ44 or IRLZ44 or just i.r. lazy?

    Sorry.

    John
     
  18. Arouse1973

    Arouse1973 Adam

    5,164
    1,081
    Dec 18, 2013
    I got this working in LT-Spice. Works fine. I think your problem is two things.
    1) The inductor value is too low as already mentioned.
    2) Putting two inductors together is not the same as having one inductor and trying to connect to the centre. You need to have mutual inductance between the inductor for this to work. Make sure the coils wound dot marking follows each other.
    Adam
     
  19. walid.anjum

    walid.anjum

    26
    0
    Dec 18, 2013
    o sory john its IRFZ44
     
  20. walid.anjum

    walid.anjum

    26
    0
    Dec 18, 2013
    how to control the floating point of circuit
     
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