555定时器是一种模拟电路和数字电路相结合的中规模集成器件，它性能优良，适用范围很广，外部加接少量的阻容元件可以很方便地组成单稳态触发器和多谐振荡器，以及不需外接元件就可组成施密特触发器。因此集成555定时被广泛应用于脉冲波形的产生与变换、测量与控制等方面。

本实验根据555定时器的功能强以及其适用范围广的特点，设计实验研究它的内部特性和简单应用。

-555 timer is an analog circuit and digital circuit of the combination of the size of integrated devices, it is excellent performance for a wide range, then add a small amount of external RC components can be easily composed of single-and multi-harmonic steady-state flip-flop oscillator, and no external components can be composed of Schmitt trigger. So from time to time integration of 555 pulses are widely used in the creation and transformation, measurement and control. This experiment based on 555 timer, as well as its powerful characteristics of the application of a wide range of design experimental study of its internal features and simple application.