voltage in parrallel circuits

Discussion in 'General Electronics Chat' started by VADER332, Mar 4, 2006.

  1. VADER332

    Thread Starter New Member

    Mar 4, 2006
    1
    0
    How do you find the voltage in a parrallel circuit if it is not given?

    Ex. if you had 3 resistor 1ohm,2ohm, and 3ohms split into 3 branches with a 500mA current
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Without a diagram to go by it is tough to figure out what you have described.

    hgmjr
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    You have not given enough data to us. With the 3 resistors in parallel, the equivalent resistance will be less than the smallest discreet resistor, so Rt will be under 1 ohm. With no additional resistance given, we can only suggest a very low source voltage that will source the 500 mills current.
     
  4. Grant

    Member

    Mar 5, 2006
    17
    0
    Hello Vader,
    The three resistances in parallel will give a total resistance of 0.55 Ohms-(using resistances in parallel equation). If you have a total current of 500mA then simply using Ohm's Law we have E=IxR
    (500mA is 0.5 Amps)
    E= 0.5x0.55
    E= 0.275 Volts
    Hope this explains it to you.
    Cheers,
    Grant
     
  5. alva

    Member

    Dec 14, 2005
    12
    0

    If the current is 500 mA before splitting up between the 3 branches, then you need to solve R then you can get the voltage. E =IR.

    For parallel resistors you can simply add the ohm value reciprocals and then use the reciprocal of the total. e.g. 1/1 + 1/2 + 1/3 = 6/6 + 3/6 + 2/6 = 11/6 = 6/11 =.545 or .55 ohms; then solve for E : E= .55 ohm x .5 A = .275V
    And in a parallel circuit the total resistance will always be less than the lowest ohm resistor, in this case 1 ohm.
     
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