As a result of their jobs, both electrical engineers and technicians come into contact with inductors regularly. Understanding inductance and related parameters ensure that systems perform at their best. Even if you aren't a specialist in inductors, having a basic understanding of their functions and operating principles is important for those who use them.

The flow of varying electric currents through a coil is very normal. A shift in the magnetic field, for example, is caused by an AC flow. A secondary current is induced as a result of the change in magnetic fields. The source current is opposed by the secondary current. Simply put, inductance (self-inductance) is characterized as an electric circuit's ability to resist changes in the current flowing through it.

Inductance is calculated using the equation e = –L(di/dt). Inductance is denoted by the letter L in the equation, and it is the sum by which the rate of change in currents is multiplied to get the EMF (electromagnetic force). The constant L refers to the self-induction coefficient, which is measured in Henrys (H). It is regarded as negative in the equation to show that the inductance voltage is polarized in the opposite direction as the source voltage.

The number of fluxes that connect a coil determines the total amount of inductance it has. The flux is determined by the coil size. Flux is often affected by custom coil winding. The presence, or lack thereof, of magnetic material in a core, is another key factor to consider.

Solution for calculating Inductance of Toroids

• Total number of turns: N

• Magnetic field inside toroid: B = µ0I 2Ï€r

• Magnetic flux through each turn (loop): ΦB = Z b a BH dr = µ0INH 2Ï€ Z b a dr r = µ0INH 2Ï€ ln b a • Inductance: L ≡ NΦB I = µ0N2H 2Ï€ ln b a

• Narrow toroid: s ≡ b − a  a ln b a = ln _x0010_ 1 + s a  ' s a

 • Inductance: L = µ0N2 (sH) 2Ï€a

 

Since the magnetic field varies with the radius from the toroid's centerline, this measurement is approximate. When the toroid radius is much greater than the coil radius, using the centerline value for the magnetic field as an average causes a small error.

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