Vacuum tubes, or electron tubes, are analog devices used to control and modify the flow of electricity. They were invented in the early 1900s based on similar principles of the incandescent lightbulbs. As current flows into the airless glass bulb, electrons radiate from a heated cathode and are attracted to an anode before leaving the tube. Since the anode is not heated, it will not re- emit electrons, forming an electrical one- way valve. This is the simplest version of a vacuum tube, but once electrical flow can be controlled in this way, additional elements can be added to modify the current to perform other functions.

This was key to the development of radios, TVs, radars, etc.

As technology advanced, transistors eventually replaced tubes. 

 Helped create modern electronics, but are now novelty items. Put on your desk to invoke curiosity and invite interesting conversation.

Look up the model number of you tube to find out it's function! 

Please allow for slight variations in appearance. You will receive one vacuum tube in its original box. 

Length: 1 - 2"