I need The Confirm Answer

Discussion in 'General Electronics Chat' started by khushal1988, Dec 10, 2010.

Thread Status:
Not open for further replies.
  1. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    Please go through the attachement and tell me that in picture the 2 image is same as 1 or its done wrong connections in 1 as in 2 please tell me confirm a bit confused.
     
    • 1.JPG
      1.JPG
      File size:
      5.2 KB
      Views:
      71
    Last edited: Dec 10, 2010
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Image 2 is an N-channel MOSFET. It is a schematic symbol, not a pad layout for a printed circuit board.

    The bottom terminal is the source.
    The left terminal is the gate.
    The top terminal is the drain.

    In image 1, everything is shorted together.
     
  3. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    actually image 1 is the layout of image 2 , i just want to know how make layout of image 2 for printing to pcb arnt they shorted together in image 2 ?? please clear my concept
     
  4. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    image 2 is schemetics and image 1 is the layout ... i want to make layout of image 2 for printing to PCB what does the symbol means rnt its 3 legs shorted together ?
     
  5. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    1. is the layout
    2. is the schematics

    the IRF540N is encircled please check the connection and tell me if i have to make nay changes to the layout according to the schematics.
     
    • 1.JPG
      1.JPG
      File size:
      53.2 KB
      Views:
      50
    • 2.JPG
      2.JPG
      File size:
      68.2 KB
      Views:
      46
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    MOSFETs are (typically) 3 terminal devices. The internal connection from drain to gate is in the silicon of the MOSFET. You do not need to add holes to exactly match the schematic diagram. Your PCB layout shows all pins of the MOSFET shorted together (including the one that doesn't exist)

    What OS are you using? KiCAD Allows you to do the schematic, and using that, generate a netlist (schematic capture is the term). From that netlist and a component database, KiCAD offers a PCB autoplacer (parts), and autorouter(traces) for the netlist, so all connections are connected.

    Simpler circuits can be done by hand and thinking in "mirror image", but once over around a dozen components are involved, people new to making boards usually have a mistake or several. Especially with ICs and Pin locations when looking at the bottom side.
     
  7. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    I use express pcb bt i have problem in irf540 , please chk da connections of those only
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Your schematic is missing part numbers and values for the ICs and the passive components.

    It would help us to help you if you will tell us more about these, and the purpose of your circuit.

    Right now, if you etched the board as-is, you would have all of the MOSFETs shorted, and you would have a bright flash and smoke when you turned on the power.

    Here is a pad layout for an IRF540 standing vertically. Note that the red areas are thick traces connecting to wire pads, just so you can see what pins are what:
    [​IMG]

    The grid is 0.05" spacing. The IRF540 pins are 0.1" spacing. Note that the drain is also connected to the tab, although shown only as a white bar in the layout.
     
    Last edited: Dec 10, 2010
  9. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    So how do design the mosfets according to schemetics ? Where to give connection from the resistors to mosfet which pin?
     
  10. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I have edited my post since your last reply.

    You have C1 and C8 installed upside-down. Normally, the straight "plate" goes towards more positive, the curved "plate" towards more negative.

    Your layout could be much more compact; the traces are very long and narrow.

    You would be much better off if you had shorter and wider traces.
     
  11. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    The MOSFETs, everything inside the circle is inside the package (TO-220 or whatnot). You simply use the 3 wires coming out of the circle to connect to the rest of the components. Think of it as a BJT transistor if that helps.

    The terminals are Source, Drain, and Gate. This is similar to Collector, Emitter, and Base in a BJT.
     
  12. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    In layout u attached ? Gate nd source are nt connected while in schematic it is connected nd second point is that from 4 nd 7 pin of ir2111 a 47 ohm resistor is conected nd wire given to ir540 i just wana know to which pin wire is connect
    ed , as i dnt understand ds thing ??
     
    Last edited: Dec 10, 2010
  13. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Please try to use proper English and proper abbreviations. If you use "phone texting" type of abbreviations, there is a greater chance that misunderstandings will occur. I'm going to have to re-write your post as I understand it, which takes more of my time.

    I thought you simply wanted to know what the pads for the IRF540 itself should look like?

    I showed you which pins are which, by the use of wire pads that are labeled.

    The upper IR2111 pin 7 is connected to one end of R4, and the other end of R4 is connected to the gate of Q1.

    The upper IR2111 pin 4 is connected to one end of R5, and the other end of R5 is connected the gate of Q2.

    The source terminal of Q1 is connected to the drain of Q2, the upper IR2111 pin 8, lower side of C2, and pad A.
    Does this explanation help at all?
     
  14. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Have a look at the attached; I just did a portion of your schematic. Q1, Q2, R4, R5, and an IR21xx driver.
     
  15. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    Sorry for typing short words it was greatly explained but in the figure layout its a bit cobfusing overlaps as double sided board as i know only single sided can u make a layout for me to understand for a single side board
     
  16. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,795
    951
    That IS a single layer layout in the Sgt's attachment.

    Your level of understanding seems in-adequate of the task. Is there someone you know who could assist you in person? The communication here is slow and takes many hours or days to complete a topic.
     
  17. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    His diagram is a single sided board. The green pads are separate to mark them as component pads, think of them as blue / copper. The white items are the top side components, there are no traces on the top side of the board.
     
  18. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    can any one design layout for me from my schemetics image in my older post by name of 2.jpeg , because i am not good in designing layout but this is my final year project please if any one can send me the layout designed in Protues or Eagle or Tina or Express PCB .
     
  19. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    We don't do that for students.

    The whole point of you being in school is for you to learn something.

    If we did it for you, you would not learn anything except how to get someone else to do your work for you.

    Here is a good site to learn about making PCBs:
    http://www.smps.us/pcb-design.html

    Sparkfun's Cadsoft Eagle tutorial is a pretty good one:
    http://www.sparkfun.com/tutorials/57
    Start from the beginning and do the whole thing as they describe it.

    Keep your traces as short and as wide as you can make them, yet still leaving at least 8mm between traces. The wider and shorter your traces are, the more current they can carry, and the fewer problems you will have due to parasitic inductance.
     
  20. khushal1988

    Thread Starter Member

    Nov 12, 2010
    70
    0
    i have short time left for presenting a demo i ll for sure learn but at the moment i need help please donot refuse make me a circuits layout so i could print it out shall be thankful to you sir.
     
Loading...
Thread Status:
Not open for further replies.