your view about my PCB

Discussion in 'The Projects Forum' started by eric_s88, Nov 27, 2012.

  1. eric_s88

    Thread Starter Member

    Apr 20, 2011
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    Hi everyone,

    I've designed a PCB in Altium Designer for the first time, and I would like you see it and tell your sight of view, I mean what you think about it? , whats wrong? what would be better if I had done? about component places tracking, etc.

    http://www.4shared.com/zip/VoGj1zCW/PCB.html
     
  2. nerdegutta

    Moderator

    Dec 15, 2009
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    I don't have an account at that site, and I will not register. How about you make a screenshot of the pcb, save it as an PNG and upload it here? Then every member can see it and comment. :)
     
  3. eric_s88

    Thread Starter Member

    Apr 20, 2011
    157
    1
    Hi , I posted the original file to get more precise comments :) I didnt know we should have an account to download that, I actually posted the download link. anyway, as you say, I made 3 screenshots of my PCB.

    Board Dimensions : 90.932*30.48 [mm]
    Schematic(sorry for poor quality) :
    [​IMG]

    2D mode with top overlay layer:
    [​IMG]
    [​IMG]

    2D mode:
    [​IMG]

    3D mode:
    [​IMG]
     
    Last edited: Nov 27, 2012
  4. nerdegutta

    Moderator

    Dec 15, 2009
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    It would be nice with a schematic... :rolleyes:
     
  5. t06afre

    AAC Fanatic!

    May 11, 2009
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    I have some questions. Will this board be home made or professional made?
     
  6. John P

    AAC Fanatic!

    Oct 14, 2008
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    Does your silkscreen layer not show the part numbers? It would be easier to assemble if it did. And it's your option, but the one text item on the PCB is pin numbers for the voltage regulator at lower left, and the numbers are in unusual sequence. What's up with that?

    I think you should have electrolytic capacitors on the input and output sides of the voltage regulator. Bigger on the input.

    The 6-pin connector (or is at an optoisolator?) on the left only has 2 pins connected. And the bottom right pin of the 2 large rectangular components (relays, I assume) is likewise unconnected. Maybe that's intentional.

    It looks as if you're installing the connectors on the right into square holes. I doubt if that's really going to happen!

    There is one rather tortured trace, from the base of the top transistor (TO-5 packages, haven't seen them in years!) to its resistor. If you moved the Gnd trace at its left to the blue layer, you'd have a straight shot between the components. Most likely you could use TO-92 packaged transistors, which are smaller and cheaper and don't have live cases.

    Is the IC an op amp? I'd suggest a 0.1uF capacitor on its power supply, as close to the chip as you can get it, with short traces.
     
    Last edited: Nov 27, 2012
    eric_s88 likes this.
  7. eric_s88

    Thread Starter Member

    Apr 20, 2011
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    I edited the post, and placed the schematic :)
     
  8. eric_s88

    Thread Starter Member

    Apr 20, 2011
    157
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    It will be a professional made ;)
     
  9. eric_s88

    Thread Starter Member

    Apr 20, 2011
    157
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    Sorry for missing information. now I added a picture at the top post, and there is the name of the components.

    about voltage regulator, in the library of altium designer the 7805 regulator schematic and footprint had this sequence of numbers (1:input , 2:eek:utput, 3:GND)

    I placed 2 capacitors of 100nF in input and output of 7805 regulator(at the top left )

    the 6pin component is an on/off switch. and about the relay, yes the right bottom pin is not connected. Its the normally close mode, that is not needed.

    The connectors with square holes, are phoenix 2pin connectors , and as I see them, they have larger square pins than other components, its wrong to place square pads?

    The IC is Attiny13 uController, and have a 100nF Capacitor from its VCC to GND
     
  10. t06afre

    AAC Fanatic!

    May 11, 2009
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    The board looks kind of autouted, is it? The tracks going from the releys to P1 and P2 looks kind of flimsy. Perhaps also consider wider tracks for power supply lines
     
  11. eric_s88

    Thread Starter Member

    Apr 20, 2011
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    Yes it is :) I just edited some tracks . the width of tracks is now 0.5mm for all of them, is that ok for power supply or.. ? the circuit will need at most 110 mA current.
     
  12. takao21203

    Distinguished Member

    Apr 28, 2012
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    Isn't a critical design. But why not increase track width.
     
  13. eric_s88

    Thread Starter Member

    Apr 20, 2011
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    except the track width , whats wrong with design? let me know your view
     
  14. takao21203

    Distinguished Member

    Apr 28, 2012
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    This was my first PCB design.
     
  15. eric_s88

    Thread Starter Member

    Apr 20, 2011
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    was it a powerful design or what? :confused:
     
  16. takao21203

    Distinguished Member

    Apr 28, 2012
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    It worked OK as designed. Tracks a little thin.
     
    eric_s88 likes this.
  17. SgtWookie

    Expert

    Jul 17, 2007
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    You do not have reverse-EMF protection diodes across the relay coils. Because of that omission, when the transistors are turned off, there will not be a path for the current, so the reverse polarity voltage across the coil will become VERY high, causing the transistors to be blown - perhaps as soon as the 1st time you try it. You could use diodes across the coils to keep that from occurring; cathode towards positive. A 1N400x diode would work.

    10k Ohms is much too high for the base resistors. You have not mentioned what current is required for the relay coils. However, 430 Ohms for the base resistors will give approximately 10mA base current, which will allow the transistors to be well-saturated at 100mA collector current; you might get away with up to 200mA current if necessary.
     
  18. eric_s88

    Thread Starter Member

    Apr 20, 2011
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    Hi SgtWookie , as you see in the schematic and PCB with top overlay layer , I've used D1 and D2 diods (1N4148) for the protection against reverse voltage of relay coils :)

    about the base resistors. before I use 2n2222 , I used bc107 and 1k resistor on its base. but when I tested 2n2222 with a 10k resistor it worked very well (on a bread board).

    I would be happy to know your opinion more about designing of PCB :)
     
  19. t06afre

    AAC Fanatic!

    May 11, 2009
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    How much current will the relays control?
     
  20. eric_s88

    Thread Starter Member

    Apr 20, 2011
    157
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    They will drive a 100Watt lapm, I think about 500~600mA current
     
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