voltage in parallel circuits

Discussion in 'Homework Help' started by bernie, Jan 9, 2005.

  1. bernie

    Thread Starter New Member

    Jan 9, 2005
    hello all,

    i've got a bunch of voltage in parallel circuits problems that i'm having severe trouble with. i can't do a picture so i'll try to describe one as best as possible. i don't need all the answers, but just one so i can figure out what i'm doing wrong.

    Et= ?V

    resistance figures are left to right

    1. 100k ohms
    2. 50k ohms
    3. 25k ohms
    4. 25k ohms

    and amps measured on top between R1 and R2 of 10mA.

    I was trying to get total resistance and coming away with 9.09k.

    then that times 10mA = 9.09 which i know is wrong. where am i going wrong here??

    Any help is greatly appreciated!!
  2. ficr

    New Member

    Jan 5, 2005
    Since the resistors are in parallel the currents will be different but the applied voltage will be the same. The current passing throught the 100k ohm resistor is 10mA, by ohms law 1kV was applied. Since the resistors are in parallel, 1kV is also applied to them as well. Hence i2= 2mA, i3= 4mA, i4= 4mA.
    To check if all this make senese we add all the currents together to find that it= 11mA. Multiplying this current by the total resistance ~9k ohm we find that the voltage source is indeed 1kV