What was Thomas Edison’s first major commercial success as an inventor?

Thomas Edison’s first major commercial success as an inventor was the stock ticker.

After working as a telegraph operator, Edison improved devices used to transmit financial quotations. His Universal Stock Ticker, developed in the late 1860s, made the distribution of stock prices more efficient and reliable.

In 1869, Edison sold rights connected with an improved stock ticker to the Gold and Stock Telegraph Company for $40,000. The payment gave him the capital to establish himself as an independent inventor and laboratory operator.

The stock ticker is sometimes confused with Edison’s first invention, the electrographic vote-recorder. The vote-recorder came first as a patent, but the ticker brought Edison his first substantial commercial success and helped finance his later work on sound recording and electric lighting.