Calculating KVL Loop

Discussion in 'The Projects Forum' started by dukebdx12, Feb 1, 2008.

  1. dukebdx12

    Thread Starter Active Member

    Jan 29, 2008
    30
    0
    I have constucted a circuit with 5 resistors. I tried to find KVL left loop( has to be =0, in our project just very close). When I calculated it i got a negative number. I'm assumming I have messed up. I think where I did was when i soldered a node of 3 resistors I soldered them together instead of seperately. I looked at a pic of the final result and thought that it looked like the 3 wires were overlapped and soldered. Now that I look at it again it looks as each resistor wire were soldered seperately and just clipped. Do I need to re-do this?
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Please post a diagram of the circuit so that we can better tell what your circuit looks like?

    hgmjr
     
  3. dukebdx12

    Thread Starter Active Member

    Jan 29, 2008
    30
    0
    ok. give me 1 sec and I'll upload the diagram I have drawn on OrCad and I'll explain what I have done.
     
  4. dukebdx12

    Thread Starter Active Member

    Jan 29, 2008
    30
    0
    http://i186.photobucket.com/albums/x207/dukebdx12/hw3.jpg

    here is a diagram. This is what I have done. I soldered the node R1,R2,R3 together on the circuit board(on accident) by overlapping the wires and soldering. Can that affect my calculations? If this is not the problem then I must have messed up somewhere with calculations. Of finding KVL left loop I have taken my VLeftBattery voltage - R1 - R3 + R4 and I got a negative number.
     
  5. dukebdx12

    Thread Starter Active Member

    Jan 29, 2008
    30
    0
    nevermind. I just re-calculated the board with my multimeter and for V1 i had got 8.54 and i just re-did it and have got 8.38 twice so now for the left loop I have got .03 which is very close to 0
     
  6. Eyas

    Member

    Dec 23, 2007
    10
    0
    Your proble is that you assume the direction of I3 from down to up since the voltage is + up and - down.
    OR, you can leave the direction of the current I3 as it is and this will make the voltage V3 as + down and - up

    One Advice:
    if you assume the direction of a current, label the polarity of the voltage such that the current enter the + and leave the - terminal.
    OR:
    if you assume the polarity of the voltage, label the current such that the current enter the + and leave the - terminal.

    In both cases if you get a negative reading of current or voltage, then the real direction of current or voltage is the reverse.

    GOOD LUCK
     
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