The modern transformer, now quite generally used in the commercial distribution of electrical power in the cities of the world, ranks next to the dynamo in importance in the electrical world. The transformer is an invention which embodies. the practical application of Faraday's first experiment in current induction, in which a closed iron ring carrying a primary coil and a secondary coil was used.
©1932 by Iowa State Teachers College
Science Bulletin: Vol. 4:
5, Article 6.
Available at: https://scholarworks.uni.edu/science_bulletin/vol4/iss5/6