MYTUTOR SUBJECT ANSWERS

1102 views

How to i calculate total resistance in a circuit?

Total resistance in a circuit depends on whether the resistors are in series or parallel since this determines which equation is to be used.

In series, resistors are essentially lined up next to each other so the total is simple since it is just the sum of the resistors resistance in ohms.

e.g. if a circuit has one 10ohm, one 45ohm and one 235ohm resistor in it, all three of which are in series, the total resistance is (10+45+235)ohm = 290ohms

In parallel each resistor is on its own path for the electricity to follow and as a result the equation is not quite the same, we use the equation:

 1/Rtotal = 1/R1 + 1/R+ 1/R..etc

e.g. a circuit has 3 resistors all in parallel. Their resistances are 25ohm, 5ohm and 100ohm respectivley, what is the total resistance of the circuit?

1/Rt = 1/25 + 1/5 + 1/100

1/R= 4/100 + 20/100 + 1/100

1/R= 25/100

100 = 25Rt

R= 4ohms

often the answer will be a fraction when calculating a parallel due to the fractions involved in the total calculation however i used a simpler calculation for the example to demonstrate the equation's use

Matthew K. GCSE Maths tutor, GCSE Physics tutor

2 years ago

Answered by Matthew, a GCSE Physics tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

168 SUBJECT SPECIALISTS

£18 /hr

Liam M.

Degree: Mathematics (Bachelors) - St. Andrews University

Subjects offered:Physics, Maths

Physics
Maths

“I have a real passion for Maths and Physics and would relish the opportunity to pass this passion on to others! ”

£18 /hr

Abhinav T.

Degree: Medicine (Other) - University College London University

Subjects offered:Physics, Maths+ 2 more

Physics
Maths
Chemistry
Biology

“Confirming understanding by verbal confirmation and communication so as to ensure clarity and confidence during the learning process and progression.”

MyTutor guarantee

Ashika V. GCSE Maths tutor, A Level Maths tutor, IB Maths tutor, 13 P...
£24 /hr

Ashika V.

Degree: Physics (Masters) - Manchester University

Subjects offered:Physics, Maths+ 2 more

Physics
Maths
Extended Project Qualification
-Personal Statements-

“Hi I'm Ashika, a third year MPhys Physics student at the University of Manchester. I tutor in Maths and Physics, Personal Statements and the EPQ.”

About the author

PremiumMatthew K. GCSE Maths tutor, GCSE Physics tutor
£24 /hr

Matthew K.

Degree: General Engineering (Masters) - Warwick University

Subjects offered:Physics, Maths

Physics
Maths

“About MeI am a student studying a general engineering masters degree at Warwick University. I amfun and friendly and have a passion for maths and physics with a little bit of rugby on the side.I helped my brother whilst he was ...”

You may also like...

Posts by Matthew

How do I find the coordinates of maximum and minimum turning points of a cubic equation?

How do i solve simultaneous equations?

How to i calculate total resistance in a circuit?

Other GCSE Physics questions

How can an object accelerate without changing speed?

Why do windows around the house steam up?

What is red shift?

View GCSE Physics tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok