Dirac is a resource that was introduced to Warframe in the Empyrean update. It is used to upgrade the Railjack grid and avionics systems. Both of these are vital components for your Railjack ship.
You can get Dirac from several different sources in the game:
As a pickup during Railjack missions. It can drop from dead enemies, environmental sources such as asteroid clusters, or as an end of mission reward.
Scrapping unwanted Avionics.
Scrap unwanted wreckage.
It can be purchased from the Market for Platinum.
Dirac can be used to upgrade both the grid and avionics themselves. You can do this from the Railjack Configuration console in your Dry Dock. Each node on the grid can be upgraded, with an increasing cost for each extra point on the node.
Each extra point will increase the effectiveness of the avionic that is installed in it. Make sure you check which avionics are installed in which node, so that you are getting the additional benefits you want.
Avionics themselves can also be upgraded, once again increasing their effectiveness. Different avionics will have a different level that they can be upgraded too. The number of times you upgrade the avionic will combine with the number of times the grid node has been upgraded to give it an overall effectiveness level.
An important thing to note here is that upgrading an avionics level will cause greater draw on the overall avionics value, but upgrading the grid nodes will not. To increase your total avionics capacity, you need to research and build new reactors. Finally, to enjoy all the features in the game, players can Buy Warframe Platinum from 5mmo.com at a reasonable price.