×
Follow Us
Results 1 to 3 of 3

What is the value of the third resistor?

    #1
  1. samfulton is offline Junior Member Pro Subscriber
    Join Date
    Jan 2019
    Posts
    1
    Reputation

    What is the value of the third resistor?

    A three-branch parallel circuit has a total resistance of 385.83 ohms. Two of the resistors are 680 ohms and 1500 ohms. What is the value of the third resistor?
    Your Answer: 2180 ohms
    Why is this wrong

  2. #2
  3. kwegley is offline Junior Member Pro Subscriber
    Join Date
    Apr 2018
    Posts
    1
    Reputation
    Quote Originally Posted by samfulton View Post
    A three-branch parallel circuit has a total resistance of 385.83 ohms. Two of the resistors are 680 ohms and 1500 ohms. What is the value of the third resistor?
    Your Answer: 2180 ohms
    Why is this wrong
    Let x = third resistor
    1/R1 + 1/R2 + 1/R3 = 1/Rtotal
    Rearrange the equation
    1/Rtotal - 1/R1 - 1/R2 = 1/R3
    1/358.83 - 1/680 - 1/1500 = 1/x
    When solved x = 2200 ohm

  4. #3
  5. cbmcbride is offline Junior Member Pro Subscriber
    Join Date
    Jan 2021
    Posts
    6
    Reputation
    Quote Originally Posted by kwegley View Post
    Let x = third resistor
    1/R1 + 1/R2 + 1/R3 = 1/Rtotal
    Rearrange the equation
    1/Rtotal - 1/R1 - 1/R2 = 1/R3
    1/358.83 - 1/680 - 1/1500 = 1/x
    When solved x = 2200 ohm
    I believe this is incorrect, can you actually demonstrate your calculations!

Subscribe

Login or register to leave a reply!


Share this thread

Related Topics

  1. How to Size Transformer Neutral Resistor
    By AlexT90 in forum NETA Level 3 Exam
    Replies: 6
    Last Post: September 13, 2020, 07:18 PM

Tags for this Thread

Follow us


Explore TestGuy


NETA Certification Training


NICET Electrical Power Testing


Help and Support