Nikola Tesla played a pivotal role in the development of alternating current (AC) electrical systems, which revolutionized how electricity is generated and distributed. Tesla's innovations included the design of the AC motor and the transformer, facilitating long-distance electrical transmission. His rivalry with Thomas Edison, who advocated for direct current (DC), underscored the advantages of AC technology, leading to its widespread adoption. Tesla's contributions have profoundly impacted modern power systems, enabling the efficient delivery of electricity that we depend on today.