二、组合电路与时序电路的特点 1.Combinational circuits（组合电路) The output level is dependent on the present input levels.(输出仅决定于输入) ◆No storage element.(储存单元) ◆No Feedback.(反馈) 2.Sequential circuits(时序电路) The output level depends not only on the present value of inputs,but also on past inputs. Employ storage element ◆Feedback involved二、组合电路与时序电路的特点 1. Combinational circuits（组合电路） ◆The output level is dependent on the present input levels.(输出仅决定于输入) ◆ No storage element. （储存单元） 2. Sequential circuits（时序电路） ◆ The output level depends not only on the present value of inputs, but also on past inputs. ◆ Employ storage element ◆ No Feedback.（反馈） ◆ Feedback involved