When was the eletric light bulb invented?

It depends what you mean by "lightbulb"; Sir Humphrey Davy demonstrated the first electric filement light in 1802, the first practical lighting system - including the bulb, was developed by Edison around 1880, but many other people were demonstrating light bulbs around that time. Edison deserves the credit for creating an entire system for generating and distributing electricity - without that, the lightbulb would be pretty useless.