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Posts posted by Virus

  1. Hero999

    I have got it this far, please see attached,

    Any suggestions on this,

    Can the OPTO be turned on more gradually (or is it only on/of like shown), it will allow for a faster charge to get to 550v in 4.7 msec needed, but then it needs to flatten out faster and not still rise on the out put.

    Can currant regulation be done with a 555 on the primary side?



  2. I have looked at LT3751 chip designed to do this fly-back circuit, the data sheet circuit is running nice in LT spice, but I could not get a bread-board or a fully built pcb version to work, (lease see attached)

    So KISS is the next step using a 555 timer.

    Thanks Virus


  3. Hi Guys

    I need a circuit that can charge (1 or 2) - 2.2uF cap(s) to 550v in ±4.7m sec. I do need the pri and sec grounds to be isolated.

    This circuit does a good job ( according to LT Spice) please see attached, but I need to replace Q2 with an OPTO to get the isolation as needed and would appreciate any feedback !

    I have stick and paste this circuit from various diagrams on the web to get it working thus far.

    Any suggestions and advice I desperately need at this stage.



  4. Hi Hero999

    Attached 2 x jpg's, 1st the original schematic (I have changed the number of turns on the transformer Primary = 13 turns and Secondary = 360 turns), 2nd jpg (simplified circuit) is what I have in mind,

    I did think that it should be possible to charge the caps using diodes but no idea how to do it, and them have them discharges them separately with separate mosfets trigger circuit

    Thank you for helping me.




  5. Hero999

    Thanks for your response, I need the caps to be isolated from each other, with common negative after each has been rectified, as each cap will be discharged separately, 

    I did wind the secondary 2 wires is parallel simultaneously, but the transformer seems to heat up fast, and wonder if there would be a different way of winding it.

    The idea is to save components/space and rather use 1 oscillator and charge 2 caps, rather than having 2 oscillator, 4 mosfets, 2 transformers, etc to get the work done. If 2 of each is the answer then so be it, but if I can save, hey why not ?  ;D

    Any suggestions?

    Thank you


  6. Hi guys/galls

    Would appreciate some advice.  ;D

    I intend to build a cdi circuit for my car, but with a slight difference and need some advice on a modification on the transformer.

    I need to charge 2 x 1 uF caps at the same time,

    normally the transformer would be 1 primary and 1 secondary winding for the transformer. 12v primary to ±200 v secondary.

    When winding the transformer, on the secondary’s, do I need to wind the  2 wires together on the core, which will give me 2 separate secondary’s, to charge the caps.


    do I need to wind a single wire with a center tap (with equal turns on each side) to give me 2 separate secondary’s,
    or would either methods be right.


  7. Hi
    I realized that D2 was at the wrong place, I have redrawn the circuit and it should work now as attached, can you please confirm the component values, (I will replace the Triac as it is probably fried,)
    Now back to the first questions in this post,
    Question :
    What resistor values must I use for the gates on the BTA08-600 and the 2N6509 respectively to get them to fully switch on?
    What amperage value switch should I use as a toggle switch?
    I also know that there is a diode missing that will protect the capacitor from the back EMF, will D3 do the job in this circuit?

    Any suggestions to improve this circuit?




  8. Guys

    By whisper I meant irritable, nagging, down warring sound, doesn’t mater how soft it is it will catch on to you. I will accept a whisper any day.

    What the use of trying to get rid of the fan noise, and replacing it with electronic noises.

    Can PWM on a 12v case fan’s, be quiet enough, to be used in this task, or should I stick with the original diagram (reply no 14).

    There’s got to be a way.


  9. Allvol

    How was your golf day?

    Thanks for the links, interesting info.

    The best I can describe for you what I want to do is, if it is at all possible for you to build the circuit in Rely 14, 3 components only.

    You can adjust the trim pot for the fans to come to a dead stop when your PC is cold, just switched on, with the thermistor in place close to the CPU heatsink, ( by playing around until you get a good position for the thermistor) it will easily control the fans from 0 % to

  10. Hey DAZZA

    See in what big letters I type, (eyes isn’t that good any more), please save me 10 page of reading, and tell me...

    Again, sorry for being so nosey, what is the “…hydrogen project,” for ? ? ? ?

    WHAT DO YOU WANT TO DO WITH A “ hydrogen reactor chamber . . . “, WHAT IS THE END PURPOSES.

    I, myself am very interested in alternative energies etc. Would it be for such an endeavor that you purpose this project ?



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