国产精品久久久久久久久,四季AV一区二区夜夜嗨,日韩精品无码中文字幕电影,www.五月婷婷.com

=====================================

=====================================

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

???????????????????????????????????

????聯(lián)系人：鄭阿清                              ????                       
????手 機(jī)：18106937709（微信同號）????
????QQ: 3007272972                          ????

?????????????????????????????????????????????

 and the armature will overcome the pull of the return spring to the core under the action of electromagnetic attraction, thus, the moving contact of the armature is driven to engage with the static contact (normally open contact) . When the coil is turned off, the magnetic attraction disappears, and the armature returns to its original position in the reaction of the spring, causing the moving contact to engage with the original static contact (normally closed contact) . In this way, suction, release, so as to achieve in the circuit of conduction, cut-off purposes. The relay's normally open and normally closed contacts can be distinguished as follows: when the relay coil is not energized, the static contact in the open state is called normally open contact;. 2. The working principle and characteristic of the thermal spring relay is a new type of thermal switch which uses the thermal magnetic material to detect and control the temperature. The utility model is composed of a temperature-sensing magnetic ring, a constant magnetic ring, a reed pipe, a heat conducting mounting plate, a plastic substrate and some other accessories. 

????????????????????????????????????

夏叔叔走了，秋阿姨忙著給樹木換上了漂亮華麗的金裝。登高望去，樹林猶如一片茫茫的金海。秋風(fēng)掠過，樹葉紛紛掉下，有的像蝴蝶翩翩起舞，有的像黃鶯展翅飛翔。地上滿是樹葉，像鋪了一層厚厚的金毯。 

????????????????????????????????????

????????????????????????????????????