With Buen partly with the transistor. I was actually servicing TV sets and radios as they were being introduced including solid state diode devices and the very first I.C.s that were used. However without the triode valve that was developed by L. D. Forest, which was really a development of the cathode ray tube(vacuum valve), the transistor would never have been a required concept. The triode valve allowed amplification of minute electrical signals and led to the development of radio transmission and reception including, eventually, the early radar systems. Once radio transmission was an everyday thing the need for portable devices became paramount, not least with the military. Although portable sets were made, and used, they were unreliable, hard to power and heavy. The need for smaller lighter devices, the development of plastics and the P.C. board made the transistor a device waiting to happen. Also the better understanding of atomic theory, helped by oscilloscopes using triode valves helped understand tunnelling in the materials used to make the early transistors. So for me the Triode valve edges it. It is indeed a thing of beauty and made all things we now take for granted possible, including transistors and an array of devices since.