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Posts posted by faizanbrohi

  1. The TL081 and most other opamps have an absolute max supply voltage rating of 36VDC. The project with your 24VAC transformer will have a supply voltage total of about 40VDC when it has low output current. A 741A opamp and a few others have a max supply voltage of 44V and the OPA445AP has a max supply voltage of 90V

    You Said this earlier for the 3A PSU and by the way how is the heatsink for the 3A PSU.
  2. As the Site says

    '' A good starting point is using 4 turns for each primary (that is, 4 turns, centre tap and another 4 turns IN THE SAME DIRECTION). To calculate the number of turns of the secondary winding, multiply by the turns ratio. For example, if you want to build a +/-30V supply, the turns ratio is 30/13.8=2.2 approx, so wind 2.2 x 4 = 8.8 turns (better 9 turns, to overcome the diode losses) for each secondary (that is, again, 9 turns, centre tap and another 9 turns IN THE SAME DIRECTION). ''


    ''Another possibility is using a toroid. You can extract it from a BIG power inductor. As a guide, a 4cm diameter toroid with a section of about 1cm2 can be used for a > 250W SMPS. Winding is a little bit more complicated than with ETD cores but with a little practice is not too difficult either.''


    THe Idea is we can use it to make a >250W power supply using 4cm toriod and some wires. For my Output i would require

    55/13.8 = 3.98 which is 4 turns and 4 x 4 = 16 turns . the problem is do i require a biggger toriod than the 4cm one ? If yes how big.

  3. I can use MJ15024 in this configration , they are 250W power transistors , to increase power , beacuse MTP75N06 is not manufactured as well as MTP60N06
    THis only Leave BUZ11 and IRF540 , which can be found . but if i use MJ15024 in parallel combination with a good heatsink will it work

    Can You tell be a more simpler method , how i can order a transformer with input ratings and output ratings . so it is easy. (ie input voltage , centre tapped , output input current)

  4. Well Here is another Amplfier i found of 1.5 KW how is this Baby . this can drive upto 1.5KW , this is insanity , but wait just calculate how many batteries  :o Godd Help me . No way , i neeed something like a ferroresonant transformer and a square wave inverter that's allll  ;D

    Further More this is the fans Pic , i am just asking do i include two fans on one heatsink or not  ???. I am Eager to use one fan per heatsink . THe Fans are rated 12V @2.2W and 200mA approx . and no i am not using these heatsinks for the inverter , i am using them first for the M250 Amplfier , Stereo 500W x 2 , 250 Watt per channel .



  5. Well Thank God I got the Transistors at a low price , farnell is toooo expensive , i have bargained for Rs 1000 for  8 transistors , one transistors cost Rs 125 which is 1.25 pounds and 0.73 dollars i guess. so really low price. Well BEsides That i also have a 8 transisitor heatsink for only Rs 175 , which is 1.75 punds or 1 dollar approx.

    So I want to ask if this M250 can be used as a amplfier in the 500W inverter to increase power. and then use a power transformer afterwords..

  6. i have studyed just now that Class AB is about 79% efficient and Class A transformer coupled have 50% efficiency. However as far as the transformer is concerned , i have decided , a transformer of 2 x 38VAC @ 6A , with 2 x 12VDC @ 1 A for something(the other winding is seperate for from the first BUT IN THE SAME HOUSING) other then powering up a amplfier . i mean for the Detector circuits and the 10 band VU LED meter that i will insert in it .

    i will also need a bridge of 35A @ 230V , well i will begin in it later , seems like a tough project and a little expensive too . i will keep it as a mega audio project and now i will make the First Audio AMplfier i posted with PCB . i am going to draw a schematic and post it sooon.

    Wish me good luck in the exams , tommorow is my Solid state Devices and Basic Electrical Engineering paperz.

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