When did Nikola Tesla invented alternating current?

Answer 1

Tesla invented the alternating-current generator that provides your light and electricity, the transformer through which it is sent, and even the high voltage coil of your picture tube. The Tesla Coil, in fact, is used in radios, television sets, and a wide range of other electronic equipment - invented in 1891, no-one's ever come up with anything better.

Answer 2

Tesla and Edison are often given credit for discovery of AC Current. Neither actually did, but instead refined works by others.

AC Current dates back to the days of Faraday. Although, Hippolyte Pixii's works were the firstto build a working AC generator via Induction in 1830s. This would eventually lead up to the AC Transformers and generation systems by ZBD in Germany in the mid 1880s. Ferrari of Italy will create the first real uses of it - and months later Tesla will do the same in 1889, Tesla had the better press and Edison the better patent lawyers.

But neither of them invented AC current.

You can find out more with some basic web searches. Ignore the Hype - Science is the real deal. Research is your best buddy.