What is this - IMAGE 1

It is a vacuum tube 

• It is also called a VT (or) Electron tube

• The First Generation of Computers used vacuum tubes for circuitry.
• Total 17,468 Vacuum tubes used in first generation computer.

These tubes like electric bulbs produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organizations.