Mike Krzyzewski is really a famous coach of Dream Team. She has coached north america men's basketball team for some time, that's clinched numerous medals for his country. Following Londonfl jerseys supplyn Olympic was over, Krzyzewski told The Associated Press that this game will be his final one as national coach, a job he's held for seven years. He had left open the possibility of swomen nfl jerseystaying with the team beyond the London Games, when practice on Saturday said these will be his last Olympics.When asked if he was sure, Krzyzewski didn't hesitate before again saying, "yecheap nfl jerseys wholesales," this will be his last game "If we could win it, then it might be three major championships in a row, i always do not know when that has been done because we haven't usually won http://govoriotkrito.bg/libs/nflcn08.htmthe globe championships," Krzyzewski said. "It becomes an enormous thing for the program." Whatever, he's an awesome coach. His achievement are going to be remembered by the country.cheap nfl jerseys
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选择时间继电器应考虑的几个问题

2014/7/25 7:58:55点击:

 时间继电器的应用是广泛的,因此如何选择时间继电器也是我们需要掌握的。以下是时间继电器的选用方式。

     (1)时间继电器有通电延时型和断电延时型两种延时方式,选用时应确定哪种延时方式便于组成控制线路。

  (2)时间继电器动作后需要一定复位时间,复位时间应比固有动作时间稍长一些,否则,可能增大延时误差甚至不能产生延时。在要求组成重复延时电路和操作频繁的场所,更应考虑这一点。

  (3)如果对延时要求不高,宜采用价格较低的电磁阻尼式或气囊式时间继电器;反之,则应采取电动机式或晶体管式继电器。

  (4)要注意电源参数变化的影响。例如,电源电压波动较大的场所,采用气囊式或电动机式时间继电器就比采用晶体管式继电器好,而电源频率动较大的场所,,则不宜采用电动机式继电器。

  (5)要考虑环境温度变化的影响。通常,境温度变化较大的场所,不宜采用气囊式和晶体管式继电器。