毕业设计(论文)电梯自动控制模型设计.doc
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1、课题名称 电梯自动控制模型 课题需要完成的任务:1.根据技术指标进行可行性方案分析及方案论述。2.硬件的框图及电路设计。3.传感器、显示器件、各主要器件、单元电路等的选用方案,性能分析及功能介绍。4.设计硬件电路的电路图。5.软件部分流程图及相关程序设计。6.毕业设计小结。课题计划:2.273.10 查资料,进行初步方案设计。3.113.18 设计最佳方案;设计硬件电路,。3.194.10 编制程序,写毕业论文。4.114.20 修改、完善毕业论文,并做答辩准备。计划答辩时间:4.22电子信息技术系 (部、分院) 2007 年 4 月 18 日英文Diode characteristic an
2、d applicationIn all electronic circuit, all must use nearly to the semiconductor diode, it is playing the vital role in many electric circuits, it is born one of earliest semiconductor devices, its application extremely is also widespread.Diode principle of workThe crystal diode is the p-n knot whic
3、h forms by the p semiconductor and the n semiconductor, forms the space charge level in its contact surface place two side, and constructs from constructs the electric field. When does not have the external voltage, because p-n ties the diffusion current which two side loads currents concentration d
4、ifference causes and from constructs the drifting electric current which the electric field causes to be equal but is at the electric equilibrium condition.When the outside has the forward voltage bias, the outside electric field and from constructed the electric field to damp mutually disappears th
5、e function to cause the current carrier the diffusion current increase to cause to the electric current.When the outside has the reverse voltage bias, the outside electric field and from constructs the electric field further to strengthen, forms in the certainly reverse voltage scope reverse saturat
6、ion current I0 which has nothing to do with with the reverse bias voltage value.When sur- reverse voltage as high as certain degree, p-n ties in the space charge level the electric-field intensity to achieve the marginal value produces the current carrier to multiply the process, produces the massiv
7、e electron-hole pairs, has produced the value very big reverse striking current, is called the diode to penetrate the phenomenon.Diode typeThe diode type has very much, according to semiconducting material which uses, may divide into the germanium diode (GETube) and silicon diode (Si tube). Accordin
8、g to its different use, may divide into the detector diode, the rectification diode, the zener diode, the switch diode and so on. According to looks after the core structure, also may divide into the contact diode, the surface contact diode and the plane diode. The contact diode is presses with a ve
9、ry thin tinsel in the bright and clean semiconductor chip surface, passes by the pulse electric current, makes to touch a silk end and the chip reliably agglutinates in the same place, forms the PN knot. Because is a contact, only allows through the small electric current (not to surpass several doz
10、ens milliamperes), is suitable in the high frequency undercurrent electric circuit, like radio detection and so on.Surface contact diode PN knot area big, allows (several to arrive safely through the big electric current several dozens is peaceful), mainly uses in the alternating current transformin
11、g the direct current the rectification in the electric circuit.The plane diode is the silicon diode which one kind specially makes, it not only can through the big electric current, moreover the performance stable is reliable, uses in the switch, the pulse and the high-frequency circuit.Diode electr
12、ic conduction characteristicThe diode most important characteristic is the folk remedy guide electric properties. In the electric circuit, the electric current only can from the diode positive electrode inflow, the cathode flow out. Under explains the diode through the simple experiment to the chara
13、cteristic and the reverse characteristic.1、characteristic In the electronic circuit, meets the diode positive electrode in the high electric potential end, the cathode meets in the cold end, the diode can lead passes, this connection way, is called to the bias. Must explain, when adds in the diode b
14、eginnings and ends forward voltage very hour, the diode still could not lead passes, flows the diode to be extremely weak to the electric current. Only then when the forward voltage achieved some value (this value is called the threshold voltage, the germanium governs and restrains is0.2VThe silicon
15、 governs and restrains is0.6V) Later, the diode will be able honest to lead passes. After leads passes the diode beginnings and ends voltage basically maintains (the germanium to govern and restrain invariablely is0.3VThe silicon governs and restrains is0.7V) Is called the diode to the pressure drop
16、.2、reverse characteristicIn the electronic circuit, the diode positive electrode meets in the cold end, the cathode meets in the high electric potential end, this time in the diode nearly does not have the electric current to flow, this time the diode is at the closure condition, this connection way
17、, is called the reverse bias. When the diode is in the reverse bias, still could have the weak reverse electrical current to flow the diode, was called leaks the electric current. When the diode beginnings and ends reverse voltage increases to some value, the reverse electricity inoperables for lack
18、 of a quorum increases suddenly, the diode will lose the folk remedy to the electric conduction characteristic, this kind of condition will be called the diode penetrating.Diode main parameterUses for to express the diode performance quality and the applicable scope technical specification, is calle
19、d the diode the parameter. The different type diode has the different characteristic parameter. Speaking of the beginner, must understand following several main parameters:1、volume correction to operating currentMost Taisho which is refers to when diode long-term continuous working allows to pass to
20、 the magnitude of current. Because electric current through pipe time can cause the tube core to give off heat, the temperature rise, the temperature surpasses the tolerance range (the silicon tube is140About, the germanium tube is90When about), can cause the tube core heat but to damage. Therefore,
21、 in the diode use do not have to surpass the diode volume correction to the work magnitude of current. For example, commonly used IN4,0014,007The germanium diode volume correction to the operating current is 1A。2、highest reverse working voltageAdds when the diode beginnings and ends reverse voltage
22、as high as a definite value, can penetrate the pipe, loses the unilateral conduction ability. In order to guarantee the use security, has stipulated the highest reverse working voltage value. For example, the IN4001 diode reverse pressure resistance is 50V, the IN4007 reverse pressure resistance is
23、1000V.3、reverse electrical currentThe reverse electrical current is refers to the diode in the stipulation temperature and under the highest reverse voltage function, has flowed the diode reverse electrical current. Reverse electrical current smaller, the pipe single direction electric conductivity
24、is better. The worth noting is the reverse electrical current and the temperature has close relationship, probably the temperature every time elevates 10, the reverse electrical current increases a time. For example 2AP1 germanium diode, in 25 oclock reverse electrical currents if is 250UATemperatur
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