What were the very first transistors known as?

The very first transistors were known as point-contact transistors. These early transistors were invented in 1947 by John Bardeen, Walter Brattain, and William Shockley at Bell Laboratories. A point-contact transistor consists of a small piece of semiconductor material, usually germanium, with two metal contacts (or "points") placed very close to each other on its surface. The operation of this type of transistor relies on the ability of current to flow through the semiconductor material between the two contact points when a small input current is applied to one of them.

This design marked a significant advancement in electronic technology, moving from vacuum tubes to solid-state devices, which are smaller, more reliable, and consume less power. The other types of transistors mentioned, such as junction and field-effect transistors, came later, evolving from the technology established by the original point-contact model. Terms like thermionic refer to electron emission processes typically associated with vacuum tubes, which does not pertain to the direct development of the first transistor types. Understanding point-contact transistors helps clarify the historical context of transistor technology and its evolution.