单片机最小系统，或者称为最小应用系统，是指用最少的元件组成的单片机可以工作的系统。对51系列单片机来说，最小系统一般应该包括：单片机、晶振电路、复位电路。

51单片机最小系统原理图加PCB(The smallest single chip system, or the minimum application system, is a system that can work with the least components of a single chip. For 51 series of singlechip, the minimum system generally should include: single chip microcomputer, crystal oscillator circuit, reset circuit.

51 MCU principle plus minimum system PCB)