Enter your coil's Number of Turns (N), the Magnetic Flux Change (ΔΦ) with your preferred Flux Unit, and the Time Change (Δt) to calculate the Induced EMF using Faraday's Law — the calculator also returns the EMF Magnitude and Rate of Flux Change so you get the full electromagnetic picture.
Induced EMF
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EMF Magnitude
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Rate of Flux Change
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Faraday's Law states that the induced electromotive force (EMF) in a closed circuit is proportional to the rate of change of magnetic flux through the circuit. When magnetic flux changes through a coil, it generates an electric field that drives current flow, which is the principle behind generators, transformers, and motors.
Electromagnetic induction is the phenomenon where a changing magnetic field generates an electric field and induces voltage in a conductor. This occurs when there's relative motion between a magnetic field and a conductor, or when the magnetic field strength changes over time.
Enter the number of turns in your coil, the change in magnetic flux with its unit, and the time period over which the change occurs. The calculator uses Faraday's Law formula: EMF = -N × (ΔΦ/Δt), where N is turns, ΔΦ is flux change, and Δt is time change.
The negative sign represents Lenz's Law, which states that the induced EMF opposes the change in magnetic flux that created it. This is a consequence of energy conservation - the induced current creates a magnetic field that opposes the original change.
Magnetic flux is measured in Weber (Wb), with smaller units like milliweber (mWb) and microtesla·square meter (µT·m²). The induced EMF is always expressed in volts (V). Time can be in seconds, milliseconds, or minutes depending on your application.
The induced EMF depends on three main factors: the number of turns in the coil (more turns = higher EMF), the rate of magnetic flux change (faster change = higher EMF), and the area and orientation of the coil relative to the magnetic field.
Faraday's Law is fundamental to many electrical devices including electric generators, transformers, induction motors, wireless charging systems, and induction cooktops. It's also the principle behind electromagnetic braking systems and many types of sensors.
The induced EMF is directly proportional to the number of turns in the coil. Doubling the number of turns will double the induced EMF, assuming all other factors remain constant. This is why transformers use coils with different numbers of turns to step voltage up or down.