A modern Tesla coil is an excellent multidisciplinary example in undergraduate STEM teaching. It incorporates several concepts from physics and electrical engineering. For example, Ampere’s law and Faraday’s law are concepts in physics while an LC circuit, an RLC circuit, and the properties of a transistor are concepts in electrical engineering. A Tesla coil shows the intimate relationship between electricity and magnetism. Ampere’s law states that a current induces a magnetic field and Faraday’s law states that a changing magnetic flux induces a voltage. In a classical Tesla coil, a spark gap switches the current on and off flowing through the primary coil. Meanwhile, in many modern Tesla coils, a transistor is used instead of a spark gap, since it can switch on and off very quickly using a lower voltage. Several papers described how modern tesla coils work. However, the designs of modern Tesla coils were complicated and the mathematical descriptions for Tesla coils were beyond undergraduate students’ level. This paper describes a modern Tesla coil by providing mathematical details that are appropriate for undergraduate students’ level. To satisfy the educational purpose of this paper, we also choose the simplest design for a modern Tesla coil. The primary circuit in a modern Tesla coil used here is a parallel RLC circuit. We show that it can play the same role as the series RLC circuit of the primary circuit in the classical Tesla coil.

Tesla coil, ampere’s law, faraday’s law, electromagnetic oscillator, transistor