Wittgenstein is a TLW-728 Super Computer Prototype who appears in The Brave Little Toaster Goes to Mars and The Brave Little Toaster to the Rescue. He is powered by a very rare cathode tube called a WFC 11-12-55. He was outmoded when transistors were invented. Later he got a terrible virus that infected his tubes, causing him to not properly function anymore. He stars in the song Chomp and Munch and is voiced by Brian Doyle-Murray.
The appliances learn that Robbie, the Master's baby, has been transported to the planet Mars, and the gang embarks on rescuing the Little Master. The gang contacts their old college buddy, Wittgenstein, through the computer, and he gives them the equipment that they need to get: a ceiling fan to fly, a laundry basket to travel in, a microwave oven and microwave popcorn (with cheddar cheese flavoring) to help them fly. After they get all the stuff they need, the appliances head off to Mars, and along the way they're encountered by singing balloons ("We're Floating").
The appliances first find Wittgenstein in the basement, alone and abandoned. The miserable supercomputer reveals that he is living on one rare tube named the WFC 11-12-55. The appliances learn that unless they find a replacement fast, Wittgenstein's tube will blow and lead to his apparent death. In an attempt to revive Wittgenstein to his superior state, Radio and Ratso go to the college's storage building to find the hard-to-find WFC 11-12-55 tube. When they come back with the last apparent tube for miles, Radio and Ratso have a brief fight before Radio accidentally breaks the tube. Wittgenstein does his best with all his might to warn the Master about the animals getting shipped to Tartaras Laboratories, but he blows his tube with a big explosion and apparently dies.
The appliances get very mad at Radio, and he feels terrible. He then sacrifices his own tube to help, which turns out to be the very rare tube they had been looking for, thus leaving himself as a lifeless appliance. Apparently, the appliances replaced the tube in the nick of time; with the boosted power of the new tube, Wittgenstein wakes up, miraculously regenerates the other smashed tubes connected to himself, and is completely revived to as good as new. He then warns the Master and sends the appliances to go rescue the animals.
Wittgenstein is afterwards discovered by the people of the university and is sent to a museum, where he will never be forgotten.