In order to provide the interface circuit for the 8 × 8 non coding keyboard of scanning method, two 8-bit parallel input ports and one 8-bit parallel output port are needed in the interface circuit.
查看答案
When LED nixie tube works in dynamic display mode, only one nixie tube is lit at the same time.
A. 对
B. 错
当总效用达到最大值时,边际效用()
A. 为最大值
B. =0
C. 大于0
D. 小于0
当总效应增加时,边际效用()
A. 为正值,且不断增加
B. 为正值,且不断减少
C. 为负值,且不断增加
D. 为负值,且不断减少
无差异曲线被用于说明()
A. 消费者偏好
B. 消费者收入
C. 商品价格
D. 上述答案都对