Purpose:Demonstrate the effect of changing the number of turns in the secondary of a transformer.
Description:A "Variac" variable transformer steps down 110VAC into the primary coil of the demountable transformer. Use the variac to put 75VAC at 60 Hz onto the 250-turn primary coil of the transformer. The secondary coil is created by looping a wire around the transformer core and connecting it to the AC voltmeter. The voltage produced is approximately proportional to the number of turns in the secondary coil; the photographs above show the cases of 4 turns (top) and 8 turns (bottom) in the secondary coil.
Be sure all wires are connected before adding power, and do not disconnect or reconfigure before cutting power.