# Self Inductance " A physicist is just an atom's way of looking at itself"
Niels Bohr • Consider now a single coil/circuit/loop with N turns.  As the current in the loop changes the magnetic field and hence the magnetic flux through the loop changes.  This changing "self flux" through Faraday's Law leads to an induced emf in the circuit, • In the same manner as mutual inductance we define the self inductance of the circuit, L, as follows so that the induced emf - sometimes called a "back emf" - is given by This "back emf" always opposes the primary emf (due to Lenz's Law), as shown in the diagram at right. From above, which can be compared to the similar equation for capacitance .
• Calculating self inductance proceeds by the same steps as mutual inductance - Calculate B, calculate magnetic flux, then use the second equation above to determine L. Renee Descartes walks into a bar, the bartender says 'sir can I get you a martini 'Descartes says 'I don't think...' and he disappears. Dr. C. L. Davis
Physics Department
University of Louisville
email: c.l.davis@louisville.edu 