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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Ch5 Diodes and Diodes Circuits,5.1,The Physical Principles of Semiconductor,5.2 Diodes,5.3,Diode Circuits,5.4,Zener Diode,Circuits and Analog Electronics,Ch5 Diodes and Diodes Circuit,Ch5 Diodes and Diodes Circuits,5.1,The Physical Principles of Semiconductor,Key Words,:,Intrinsic(pure),Semiconductors,Electrons,Holes,Carriers,Phosphorus Doping(N-type),Boron Doping(P-type),PN Junction,Ch5 Diodes and Diodes Circuits,Ch5 Diodes and Diodes Circuits,5.1,The Physical Principles of Semiconductor,Intrinsic(pure),Semiconductors,Different types of solids:,Conductor,V,T,5.2,Diodes,and Diode Circuits,PN Junction Diode V-A Characteristic,Ch5 Diodes and Diodes Circuits,Current Equations,The forward bias current is,5.2,Diodes,and Diode Circuits,PN Junction Diode V-A Characteristic,Ch5 Diodes and Diodes Circuits,Current Equations,In reverse bias(when,v,D,0 by at least,V,T,),then,In breakdown,reverse current increases rapidly a vertical line,P5.1,PN Junction when T=300K,，,Find i,D,when,5.2 Diodes and Diode CircuitsP,5.2,Diodes,and Diode Circuits,PN Junction Diode V-A Characteristic,Ch5 Diodes and Diodes Circuits,5.2 Diodes and Diode CircuitsP,5.2,Diodes,and Diode Circuits,PN Junction Diode V-A Characteristic,Ch5 Diodes and Diodes Circuits,P5.2,Look at the simple diode circuit below.,Q,operating point,Load line,I,D,=7(mA),V,D,=0.8(V),5.2 Diodes and Diode CircuitsP,5.2,Diodes,and Diode Circuits,Diode Parameters,Ch5 Diodes and Diodes Circuits,V,R,The maximum reverse DC voltage that can be applied across the diode.,I,R,The maximum current when the diode is reverse-biased with a DC voltage.,I,F,The maximum average value of a rectified forward current.,f,M,The maximum operation frequency of the diode.,5.2 Diodes and Diode CircuitsD,5.2,Diodes,and Diode Circuits,Diodes,Ch5 Diodes and Diodes Circuits,5.2 Diodes and Diode CircuitsD,5.2,Diodes,and Diode Circuits,Light Emitting Diodes,Ch5 Diodes and Diodes Circuits,When electrons and holes,combine,they release energy.,This energy is often released as heat into the lattice,but in some materials,they release light.,This illustration describes the importance of the plastic bubble in directing the light so that it is more effectively seen.,5.2 Diodes and Diode CircuitsL,5.2,Diodes,and Diode Circuits,Ch5 Diodes and Diodes Circuits,Diode Models-,The Ideal Switch Model,When forward-,biased,the diode ideally acts as a closed(on)switch.,When reverse-,biased,the diode acts as an open(off)switch.,5.2 Diodes and Diode CircuitsC,5.2,Diodes,and Diode Circuits,Ch5 Diodes and Diodes Circuits,Diode Models-,The Offset Model,Si diode,：,V,on,0.7(V),（,0.6,0.8,）,Ge,diode,：,V,on,0.2,（,V,）,V,V,on,，,closed switch,V,V,on,，,open switch,5.2 Diodes and Diode CircuitsC,5.2,Diodes,and Diode Circuits,Ch5 Diodes and Diodes Circuits,Diode Models-,The,Small-Signal Model,Some circuit applications bias the diode at a DC point(,V,D,)and superimpose a small signal(,v,d,(,t,)on top of it.Together,the signal is,v,D,(,t,),consisting of both DC and AC components,Graphically,can show that there is a,translation of voltage to current(,i,d,(,t,),Can model the diode at this bias,point as a resistor with resistance as,the inverse of the tangent of the,i,-,v,curve at that point,5.2 Diodes and Diode CircuitsC,And if,v,d,(,t,)is sufficiently small then we,can expand the exponential and get an,approximate expression called the small-,signal approximation(valid for,v,d,V,on,D on,v,o,v,i,；,v,i,V,on,，,D off,v,o,=0,。,5.3 Diode CircuitsCh5 Diodes a,5.3,Diode Circuits,Ch5 Diodes and Diodes Circuits,multiple diodes Circuits,Let V,on,=0.7V,V,o,=?,5.3 Diode CircuitsCh5 Diodes a,5.3,Diode Circuits,Ch5 Diodes and Diodes Circuits,multiple diodes Circuits,V,1,(V),V,2,(V),V,o,(V),Logic output,0,0,0.7,0,5,0,0.7,0,0,5,0.7,0,5,5,5,1,5.3 Diode CircuitsCh5 Diodes a,5.3,Diode Circuits,Ch5 Diodes and Diodes Circuits,Rectifier Circuits,One of the most important applications of diodes is in the design of rectifier circuits.Used to convert an AC signal into a DC voltage used by most electronics.,5.3 Diode CircuitsCh5 Diodes a,5.3,Diode Circuits,Ch5 Diodes and Diodes Circuits,Rectifier Circuits,Simple Half-Wave Rectifier,What would the waveform,look like if not an ideal diode?,5.3 Diode CircuitsCh5 Diodes a,5.3,Diode Circuits,Ch5 Diodes and Diodes Circuits,Rectifier Circuits,Full-Wave Rectifier,To utilize both halves of the input sinusoid use a center-tapped transformer,5.3 Diode CircuitsCh5 Diodes a,5.3,Diode Circuits,Ch5 Diodes and Diodes Circuits,Rectifier Circuits,Bridge Rectifier,Looks like a Wheatstone bridge.Does not require a enter tapped transformer.,Requires 2 additional diodes and voltage drop is double.,5.3 Diode CircuitsCh5 Diodes a,5.3,Diode Circuits,Ch5 Diodes and Diodes Circuits,Rectifier Circuits,Peak Rectifier,To smooth out the peaks and obtain a DC voltage,add a,capacitor,across the output.,5.3 Diode CircuitsCh5 Diodes a,Ch5 Diodes and Diodes Circuits,5.4,Zener Diode,Key Words,:,Reverse Bias Piecew
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