Question: what is the difference between ac and dc bulb?
Answer: For a given voltage, such as 120V, there is no bulb designated as DC as opposed to AC. In general, 120V & 240V bulbs are used on AC, while 6V, 12V & 24V bulbs are used on DC. But there is nothing in any incandescent bulb that makes them prefer AC or DC. There are 12V CFL & LED bulbs intended for 12V DC battery systems.