Magnetics ```Magnetic field in a solenoid B = µ₀µᵣNI/h B = µ₀µᵣH H = NI/h B is the magnetic field in teslas or Webers per square meter H is magnetic field strength in Amps/m h is length of solenoid in meters N is number of turns I is current in amps µ₀ is the magnetic constant 1.2566e-6 H/m (or T·m/A) µᵣ is the relative permeability of the core material 5000 for pure iron 1 for air or vacuum 600 for nickel μ (µ₀μᵣ) the permeability of the material of the core A flux density of one Wb/m² is one tesla. 1 Wb = 1T·1m² for a short solenoid, with radius > length B = µ₀µᵣNI / 2R R is radius of coil Energy in an inductor in Joules E = ½LI² Magnetic field in a wire (Ampere's Law) B = µ₀I/2πr in Tesla where r is the measurement point from the wire I is current in amps µ₀ is the magnetic constant 1.2566e-6 H/m (or T·m/A) Direction of the magnetic field is determined by the right hand rule, thumb points in direction of conventional current and curl of fingers indicates direction of field. Force on a current carrying wire in a magnetic field is F = ILB B is magnetic field in tesla I is current in amps L is length of the wire Ampere's Force law, force between two wires with current. Fm = 2KaI₁I₂/r Fm is force per unit length in N/m ka is magnetic force constant = µ₀/4π = 1e-7 N/amp² r is spacing of the wires in meters I₁ and I₂ are the DC currents in the wires in amps If the currents flow in the same direction, the force points towarda the other wire Force between two magnetic poles If both poles are small enough to be represented as a single points then they can be considered to be point magnetic charges. Classically, the force between two magnetic poles is given by F = μ•qm1•qm2 / r² where F is force in newton qm1 and qm2 are the magnitudes of magnetic poles in amp-meter μ is the permeability of the intervening medium in tesla meter per ampere, henry per meter or newton per ampere squared r is the separation in meter Inductance of a solenoid L = µ₀µᵣN²A/Ln Ln is length in meters A is cross-sectional area in meters² N is number of turns µ₀ is the magnetic constant 1.2566e−6 H/m (or T·m/A) µᵣ is the relative permeability of the core material Inductance of a wire L = Ln(200e-9)(ln (4(Ln/d) – 1)) E = ½LI² Energy in an inductor Magnetics Universal Transformer EMF Law If the flux in the core is purely sinusoidal, the relationship for either winding between its rms voltage Erms of the winding, and the supply frequency f, number of turns N, core cross-sectional area A and peak magnetic flux density B is given by the universal EMF equation: Erms = 4.44fNAB ``` Home Area, Volume Atomic Mass Black Body Radiation Boolean Algebra Calculus Capacitor Center of Mass Carnot Cycle Charge Chemistry   Elements   Reactions Circuits Complex numbers Constants Curves, lines deciBell Density Electronics Elements Flow in fluids Fourier's Law Gases Gravitation Greek Alphabet Horizon Distance Interest Magnetics Math   Trig Math, complex Maxwell's Eq's Motion Newton's Laws Octal/Hex Codes Orbital Mechanics Particles Parts, Analog IC   Digital IC   Discrete Pendulum Planets Pressure Prime Numbers Questions Radiation Refraction Relativistic Motion Resistance, Resistivity Rotation Series SI (metric) prefixes Skin Effect Specific Heat Springs Stellar magnitude Thermal Thermal Conductivity Thermal Expansion Thermodynamics Trigonometry Units, Conversions Vectors Volume, Area Water Wave Motion Wire, Cu   Al   metric Young's Modulus