The 555 is an integrate circuit (chip) implementing a variety of timer and multivibrator applications. The IC was designed and invented by Hans R. Camenzind. It was designed in 1970 and introduced in 1971 by Signetics (later acquired by Philips). The original name was the SE555/NE555 and was called "The IC Time Machine". The 555 gets its name from the three 5-kOhm resistors used in typical early implementations (Reference 1). It is still in wide use, thanks to its ease of use, low price and good stability. As of 2003, 1 billion units are manufactured every year.