We present a simple method for determining the mutual inductance between two coils in a coupled AC circuit using a digital dual-phase lock-in amplifier. The frequency dependence of the real and imaginary parts is measured as the coupling is changed. The mutual inductance decreases as the distance between the centers of coils is increased. We show that the coupling is proportional to with . This coupling is similar to that of two magnetic dipoles.
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© 2008 American Association of Physics Teachers.
2008
American Association of Physics Teachers
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