Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

Wikipedia mentions that the word self in the word "self-inductance" is to differentiate it from "mutual inductance". But it does not state whether the two things are the same thing. So do the both terms mean that when I have a change in current in some thing such as coil or wire, there will be a voltage generated according to:

$V = L \frac{dI}{dt}$

where $L$ measures the inductance of the material.

share|improve this question

1 Answer 1

up vote 3 down vote accepted

"Mutual inductance" and "self-inductance" are not the same thing, no.

Suppose you have two loops (of wire, for example), loop A and loop B. When you run a current through loop A, it produces a magnetic field that fills the space around both loops. The mutual inductance between the two loops, denoted $M_{AB}$, is defined as the ratio of the magnetic flux through loop B to the current running around loop A:

$$M_{AB} = \frac{\Phi_B}{I_A}$$

You can do this calculation with loop A and loop B being two different loops, or you can do it using the same loop as both A and B (i.e. calculate the flux through the same loop that the current runs around). If you use two different loops, it's called the mutual inductance and labeled $M$ (as above); if you use just one loop, it's called the self-inductance and labeled $L$. "Inductance" is technically a general term that encompasses both possibilities, although it's common to use the word to mean self-inductance because that is the usual meaning.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.