External Circuit Posted on 10th November 201527th July 2021 by ThePD (The Project Definition) An External Circuit is the connected components that is the wires, connectors, measuring devices, current sources, etc. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Engineering and tagged electrical. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.