The Big Bang Theory NINE, 10.15pm

When pangs of jealousy join forces with a misguided attempt at Morse code, there are laughs aplenty. In “The Collaboration Contamination”, you might concur that the comforting sounds of canned laughter aren’t even needed, thanks to a visually hilarious moment between Sheldon (Jim Parsons) and Howard (Simon Helberg). Tonight, friendships are tested when Sheldon and Raj (Kunal Nayyar) confide in Bernadette (Melissa Rauch) that they can no longer handle Amy (Mayim Bialik) and Howard working together. Penny (Kaley Cuoco) and Leonard (Johnny Galecki) also learn new tactics for dealing with Sheldon.