Subject overview
Magnetism
Linear magnetic circuits, flux, field strength, reluctance and Faraday’s law.
01 Linear Magnetic Circuit
Variables
- Nturns
- 1dimensionless
- Icurrent
- Aampere
- lmagnetic path length
- mmeter
- Across-sectional area
- m²square meter
- μᵣrelative permeability
- 1dimensionless
- Θmagnetomotive force
- Aampere
- Hfield strength
- A/mamperes per meter
- Bflux density
- Ttesla
- Φmagnetic flux
- Wbweber
- Rmreluctance
- A/Wbamperes per weber
Key Formulas
Ampère’s law reduces to Hl = NI for the uniform closed path. Combining it with the linear material relation B = μ₀μᵣH and uniform flux Φ = BA gives the magnetic circuit equations. Faraday’s law relates flux change to induced EMF.
Uniform closed magnetic path with constant positive relative permeability. No saturation, hysteresis, leakage or fringing. μ₀ = 1.25663706127 × 10⁻⁶ H/m (CODATA 2022).
Calculate
Type prefixes directly: 1.5k, 250m or 20u. Results: 3 significant figures.
Uniform closed magnetic path with constant positive relative permeability. No saturation, hysteresis, leakage or fringing. μ₀ = 1.25663706127 × 10⁻⁶ H/m (CODATA 2022).
Enter the required input values to calculate.
02 Faraday’s Law
Variables
- Nturns
- 1dimensionless
- ΔΦchange in linked flux per turn
- Wbweber
- Δttime interval
- ssecond
- Uindmean induced EMF
- Vvolt
Key Formulas
Ampère’s law reduces to Hl = NI for the uniform closed path. Combining it with the linear material relation B = μ₀μᵣH and uniform flux Φ = BA gives the magnetic circuit equations. Faraday’s law relates flux change to induced EMF.
Average EMF over a positive interval. Each turn links the same flux. The minus sign follows Lenz’s law for the chosen loop orientation.
Calculate
Type prefixes directly: 1.5k, 250m or 20u. Results: 3 significant figures.
Average EMF over a positive interval. Each turn links the same flux. The minus sign follows Lenz’s law for the chosen loop orientation.
Enter the required input values to calculate.