====== AC Induction Lights Bulb ====== {{:physicsdemos:electricity_and_magnetism:electromagnetic_induction:ac_induction_lights_bulb.jpg?600|}} A small light bulb connected to a large coil is lit by magnetic induction. A time-dependent magnetic field is generated with another coil which is plugged into a Variac. The brightness of the bulb is dependent on the proximity and alignment of the two coils. One may also observe the brightness of the bulb increase when a ferromagnetic rod is inserted inside the coils. J3, A0 PIRA DCS 5K10.40