Hey there! Sign in to join this conversationNew here? Join for free

Infinite resistors help Watch

    • Thread Starter

    A circuit contains infinitely many resistors connected in parallel. Each successive resistor has a resistance of double that of the previous one.
    What is the equivalent resistance of the resistors in this circuit?

    Thank you!

    I think that the answer is Half an ohm. the first resistor has resistance on 1 ohm. The rest forms an infinite geometric series that converges.
    using the equation (1-r)/r to give the sum of the series
    1/2+1/4+1/8,... (1/2)^n r=1/2 because r is the multiplication factor 1/2 * r = 1/2 and 1/4 * r = 1/8 sp r = 1/2. you could thing of it as if you are doubling each time your reciprocal is halving each time. (1-0.5)/).5 = 1 ohm, the reciprocal of this is 1. so we have one ohm but there still that pesky 1/1 ohm resistor at the start. i think that means 1/RT = 2 so RT = 0.5
    weird question really requires a level maths not taught in physics.
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Break up or unrequited love?
    Help with your A-levels

    All the essentials

    The adventure begins mug

    Student life: what to expect

    What it's really like going to uni


    Essay expert

    Learn to write like a pro with our ultimate essay guide.

    Uni match

    Uni match

    Our tool will help you find the perfect course for you

    Study planner

    Create a study plan

    Get your head around what you need to do and when with the study planner tool.

    Study planner

    Resources by subject

    Everything from mind maps to class notes.

    Hands typing

    Degrees without fees

    Discover more about degree-level apprenticeships.

    A student doing homework

    Study tips from A* students

    Students who got top grades in their A-levels share their secrets

    Study help links and info

    Can you help? Study help unanswered threadsRules and posting guidelines

    Sponsored content:



    Find out how a Higher Education Achievement Report can help you prove your achievements.

    Groups associated with this forum:

    View associated groups
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.