Colonel Richard Williams is a character appearing in Seasons 10 and 11 of The Big Bang Theory.
Colonel Williams first appears in the Season 10 premiere episode "The Conjugal Conjecture", where he comes to Howard Wolowitz's house, asking Raj if he's there. Raj nervously tells him that he has the wrong address. He asks if Howard can meet with him at Caltech, but doesn't tell them what it's about.
He meets with Sheldon, Leonard, and Howard in The Military Miniaturization, and even though Sheldon was forbidden to talk due to his occasional insensitivity, he tells the Colonel that he is the brains of the project, and states that they can make the guidance system smaller in just 2 months.
As Leonard, Sheldon, and Howard work late at night on their project in The Dependence Transcendence, Sheldon is having difficulty staying awake. With this, they fear that may not reach their two-month deadline. Thus, they meet with Colonel Williams in his office and ask for more time; he graciously gives them two years, stating that they're not the first government contractors who were unable to make their deadline.
In The Locomotion Reverberation, Leonard and Howard finish the gyroscope without Sheldon's help. However, Colonel Williams sees that Sheldon came up with a theory to make the gyroscope even smaller, and insists that they go for it, in spite of their dismay, leading them to desperately get Sheldon to help them, to no avail.
In The Gyroscopic Collapse, as Leonard, Sheldon, and Howard enter the lab to test their finished product, they are shocked to find that their project and all their work is gone. They contact Colonel Williams via Skype to find out it was he who took everything regarding their project; he explains that they've done Phase 1 and that he'll take care of the rest. He doesn't tell them anything else, leaving Howard, Sheldon, and Leonard outraged that the Air Force just took all their work without even consulting them.