Point-contact transistor,type GET 2 c.1953

The transistor, invented by William Shockley, Walter Brattain and John Bardeeen, was announced by Bell Telephone Laboratories in 1948, revolutionising the field of electronics. The transistor was the first solid-state device which could act as a switch or an amplifier, replacing the bulky, fragile and unreliable triode valves, first introduced in 1907. Intensive research refined the device, though it was several years before it became commercially available.