The American Benjamin Franklin FRS3 (1706 - 1790) experimented with electricity using a kite, a key and lightning, proving lightning was a form of electricity. He also deduced the fact that two items can be charged negatively and positively. He coined these, and most of the other words to do with electriciy, and also invented the lightning conductor.
Thomas Edison (1847 - 1931) made the light bulb economical, making electricity useful for the first time. He also helped define how electricity works.
Alessandro Volta (1745 - 1827) invented the Battery in 1800, though electricity was known about since the Greeks.
The german Prof. Georg Simon Ohm (1789 - 1854) published his law on resistance in 1827