Electromagnetic Induction

Battle of the Currents: AC vs DC

In this course, Professor Bruce Hunt (The University of Texas at Austin) explores the history of direct current (DC) and alternating current (AC). In the first mini-lecture, we learn about the developments in the understanding of electricity and magnetism that lead to the discovery of electromagnetic induction. In the second mini-lecture, we explore magnetos, dynamos, and electric lights as we delve into the era of the incandescent light bulb, electrical power systems, and DC. In the third mini-lecture, we introduce alternating current (AC) and the notorious “battle of the currents”. In the fourth mini-lecture, we learn about transformers and their ability to provide high voltages for efficient transmission and low voltages for safe use. In the fifth mini-lecture, we delve more deeply into the battle of the currents and discuss the developments made towards today’s integrated electrical power systems, or ‘grids’.

Electromagnetic Induction

In this mini-lecture, we learn about the developments in the understanding of electricity and magnetism that lead to the discovery of electromagnetic induction. In particular, we consider: (i) the etymology of the word ‘electric’, which comes from the Greek word for ‘amber’ since amber gives off a strong charge when rubbed; (ii) Alessandro Volta (after whom the Volt is named), who devised the first electrical battery known as the ‘pile’; (iii) Hans Christian Øersted, who found that a current from a battery could exert magnetic effects; (iv) a demonstration of the electromagnetic effect discovered by Øersted; (v) the invention of the electromagnet; (vi) Michael Faraday’s electromagnetic rotation device and his discovery of electromagnetic induction; (vii) a demonstration of electromagnetic induction; and (viii) the Faraday coil and the importance of Faraday’s discoveries to the electrical power industry we rely on today.