When the current changes in a circuit containing inductance, the magnetic linkage changes and induces a voltage in the inductance:
**dy/dt = e = L di/dt**
Note that the induced voltage has a polarity which opposes the rate of change of current.
Alternatively, by integration with respect to time:
**Y = **ò**edt = LI**
The inductance **L** of a circuit is equal to the induced voltage divided by the rate of change of current:
**L = e / di/dt = dy/dt / di/dt = dy/di**
Alternatively, the inductance **L** of a circuit is equal to the magnetic linkage divided by the current:
**L = Y / I**
Note that the magnetic linkage **Y** is equal to the product of the number of turns **N** and the magnetic flux **F**:
**Y = NF = LI** |