Physics/Reciprocals

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

CoffeeintheMorning

Full Member
7+ Year Member
Joined
Dec 3, 2016
Messages
94
Reaction score
30
In parallel circuits, we see that the Resistor=1/R
What does this reciprocal mean?
Please explain like I'm five.

Thanks!

Members don't see this ad.
 
Basically for resistors in parallel, the reciprocal of the actual amount of resistance (Req) is equal to the sum of all of the reciprocals of the individual resistors in the parallel circuit.
1/Req = 1/R1 + 1/R2....

For resistors in series the actual amount of resistance (Req) is equal to the sum of all of the individual resistors in the series circuit
Req = R1 + R2....

hopefully that helps
 
Hi, the 1/R term is used to solve two or more resistors in parallel.
Now let's assume we have two resistors R1 and R2 in parallel and we want to solve them,
now the formula will be:
1/R = 1/R1 + 1/R2
After solving these use cross multiplication and you will be able to find the equivalent resistance.
You can simply use this formula, Incase of a large number of resistors like 2, 3 or 4 you can calculate equivalent resistance in parallel using this automated solution.
Since in written exams and competitive tests you are not allowed to use the web, so you should learn to solve the calculators in parallel, as well as you should know some fast tricks:

  1. Two or more resistors in parallel with same value have an equivalent value that is equal to half of single resistance. For example 5 in parallel with 5 is 2.5.
  2. Two resistors one with very large value and one with very small have an equivalent that is always equal to smallest one.
 
Top