3-Way

3-Way incandescent light bulbs allow the user to have three light output levels in one bulb. A 3-Way bulb has two filaments that can operated separately or in combination. For example, a 50/100/150 3-way bulb has a low power 50W filament, a medium power 100W filament, and, when both filaments are energized together, a high power 150W. A 3-Way bulb must be matched to a socket with 3 contacts and a switch with four positions: off, low power, medium power, high power.