Induction In A Transformer


To demonstrate that a change in the primary current induces a secondary voltage.


Demountable transformer core with coils of 46 turns and 500 turns, 1.5 volt battery, variable resistor, and lecture-demonstration galvenometer.


Setup Time

5 min.




    The 46-turn primary coil of a transformer is connected through a variable resistor to a 1.5 volt battery, and a large galvenometer is connected directly across the 500-turn secondary, as shown in the circuit diagram below. The primary current in this simple transformer is changed by sliding the variable resistor contact, inducing a secondary potential which is indicated by the galvenometer. Motion of the resistor slider and current in the galvenometer are correlated.