Inspector Gadget is the main protagonist of the series and movies. His fashion sense resembles that of Inspector Clouseau from the Pink Panther movies; his mannerisms also appear to draw on the character of Maxwell Smart, which Adams portrayed in the 1960s.
In The Cartoon Series:
Often cluelessly stumbling through any case he is given, Gadget frequently ignorantly makes foolish mistakes pertaining to surroundings and current environment, mistaking innocent bystanders (and sometimes Brain, his niece Penny's dog) for enemies, and believing that the real enemies are friends. His ineptitude always leads him into danger, but he always gets out of trouble through either his trusty gadgets (most notably his springs), Penny's interference, or pure luck.
The episode "M.A.D. Trap" is one of the few episodes in which Gadget actually shows some competence. When Dr. Claw traps him in a steel foundry, he uses his gadgets flawlessly to save Penny and Brain. Later, in "The Moral," Penny and Brain muse that it was a good thing his gadgets were in top shape. Another episode where he shows some genuine police skill was when he makes an earnest effort to catch Claw during a car chase and becomes infuriated when Claw gets away.
In the early episodes Gadget is halfway brilliant and acknowledges Dr. Claw is nearby. After the first few episodes, however, Gadget has become incompetent. Occasionally, he also inadvertently helps Penny solve the case, with his bungling either distracting Dr. Claw or setting things up for Penny to do her work.
The nearest Gadget ever gets to capturing Dr. Claw is in the opening teaser of each episode in which Gadget handcuffs a decoy metal glove, only to have a bomb explode in his face. However, this is meant to demonstrate that Claw always manages to escape justice and was never seen in any actual episode. Gadget's catchphrase is "Wowsers!".
In #9, "Race to the Finish", #11, "A Star is Lost", #22, "Sleeping Gas", #43, "No Flies on Us", #65, "Quizz Master", #73, "The Incredible Shrinking Gadget", #77, "Bad Dreams are Made of This", and #80, "N.S.F. Gadget", Gadget falls victim of the M.A.D. spells. He is voiced by Don Adams.
(Taken From Wikipedia)