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Digital Voltmeter!! on Breadboard

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by remon7, May 23, 2014.

  1. remon7

    remon7 Active Member

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    3volts chemelec about my measuring volts. also what do u mean voltage divider ?? !!! i did not get you ..
     
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  2. remon7

    remon7 Active Member

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    yeah its zero ,,Then ................
     
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  3. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    And you read these wacky voltages?
     
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  4. dave

    Dave New Member

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  5. remon7

    remon7 Active Member

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    First digit !!! its not working well !!!!
     
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  6. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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  7. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Check your bread board. The two outer rows on each side are really 4 disconnected rows on your board, I believe. The larger "white space" divides or breaks the continuity of the rows.

    e.g. The green vertical wire on the left of the pic I referenced is NOT connected to the two short horizontal green and browns that are cut off in the pic near the top of the page.

    Note: EDIT
     
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  8. remon7

    remon7 Active Member

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    wacky means ???
     
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  9. remon7

    remon7 Active Member

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    i have checked about shorting input ,,but there is no 000 results !!!
     
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  10. remon7

    remon7 Active Member

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    Yeah now its working but display showing me several random number. when i tried measure voltage about 3volts then it showed me 1 in left LED and Right LED turn off. Even in first LED is connected with IC about a, b, c, d ,e ,f ,g led. but working only b and c . sometimes g. bc connected with IC 19 number pin.
     
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  11. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    Are you getting the negative supply voltage?
     
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  12. remon7

    remon7 Active Member

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    ok i am really confused which diagram should i follow ?
     

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  13. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Remind me, are you using the 7106 or the 7107?
     
  14. remon7

    remon7 Active Member

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    I am using ICL7107 ,,,ICL7106 its not available there
    .....Derstrom8
     
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  15. remon7

    remon7 Active Member

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    I have ICL7107
     
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  16. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Then I suggest you follow the schematic for the one that calls for the 7107 :p
     
  17. remon7

    remon7 Active Member

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    but there is not pin for negative part .............
     

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  18. remon7

    remon7 Active Member

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    But you Told me Negative part is essential for this circuit ....
     
  19. remon7

    remon7 Active Member

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    another question is how could i realize that my 7 segment display is common cathode or common anode ? Even in two display has no company or model name. maybe names are removed from display back side.
     
  20. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Hmm, you're right. When I said to use a -5v display I was repeating what someone else had said--I had not looked at the schematic yet. Looking at both of them, I do not see a -5v supply in either one....? I wonder why someone mentioned needing -5v?

    You should have mentioned that when I asked what components you were using. That's why I was asking for an EXACT list of what you had. However, if your display is showing any numbers at all, then chances are you have the correct type (CA or CC). However, you MUST check your wiring connections. If you cannot find a part number for your 7-segment display, you will probably have to buy one that matches the one in the schematic, or at least one that has the same pinout (and the same type).
     
  21. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    A 1 in the left most digit only is surely a sign of overload.

    Voltage too big. ground loops or attenuator resistances wrong.
     

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