Energy stored in large coil with soft iron core flashes bulb.

Energy stored in large coil with soft iron core flashes bulb. A laminated iron core is inserted into a large coil of 1532 turns. Two 6 V.D.C. batterys are hooked up to the coil via a knife switch, and a 15 watt, 120 Volt bulb is attached in parallel. When the switch is closed, the bulb glows dimly. Most of the energy goes into the coil magnetic field. However, when the switch is released, the bulb flashes brightly. The energy from the collapsing magnetic field of the coil surges through the bulb, causing a brief flash. Note: See set-up sheet in file cabinet in 72 Le Conte Hall