[信息与通信]Analogue Electronic Principles 2.ppt
《[信息与通信]Analogue Electronic Principles 2.ppt》由会员分享,可在线阅读,更多相关《[信息与通信]Analogue Electronic Principles 2.ppt(32页珍藏版)》请在三一文库上搜索。
1、Analogue Electronic Principles,DG2X 34,Bipolar Junction Transistor,晶体管 (BJT) 的结构和符号 (symbol ),从E区到达B区的电子 (I B + I CBO), 则必有(I B + I CBO) 电子到达C区: I C =(I B + I CBO) + I CBO =I B + (1 +) I CBO =I B + I CEO (穿透电流) I B (电流放大) I E = I B + I CBO +(I B + I CBO) = I B + I C,E 区电子扩散注入 B 区,C 结强电场将其拉入 C 区, 由于到
2、达 C 区电子来自 E 区,因此反映了 E 结电压规律。,晶体管工作在放大区的电流分配关系,I CEO =I CBO + I CBO = (1 +) I CBO I CEO : 从 C 区穿透 B 区到达 E 区,穿透电流 I CEO (leakage current) 与 反向漂移电流 I CBO,晶体管的输入特性曲线 input characteristic,晶体管的输出特性曲线 output characteristic,晶体管的输出特性曲线,AC current gain,Active region,Saturation region,Cut-off region,三极管工作状态: 1
3、、放大:E 结正偏 C 结反偏 此时 IC = IB 2、截止:E 结正偏不足/反偏 此时 IB 0 3、饱和:E 结 C结均正偏 此时 IB IC,The Quality of BJT,1、截止区小(ICEO 小,温度稳定性好); 2、曲线间距宽( 高); 3、曲线平(IC 只受 IB 控制);,静态工作点 (Q点): Quiescent point、 Operating point、 Working point。,Description for an NPN bipolar junction transistor device: An NPN bipolar junction transi
4、stor consists of two PN junctions. It has a P-type base and N-type collector and emitter. When transistor operates in saturation region the two junctions of the transistor are forward-biased. For a constant base current, the collector current increases as VCE increases from 0V to about 0.7V. When tr
5、ansistor operates in active region, as a linear amplifier, the VCE exceeds about 0.7V, the collector-base junction becomes reverse-biased. The collector current depends on the base current only and is independent from VCE. Ic = IB, the bipolar transistor is a current controlled device. When transist
6、or operates in cut-off region the base-emitter junction is not forward-biased enough or so much as reverse-biased, there is no the forward base current and thus the collector current is nearly zero (when IB = 0, Ic = ICEO, the leakage current).,Transistor application,Common-Emitter Amplifier,静态工作点设置
7、: 调 RB 定 IBQ,调 RC 定 VCEQ ,使 BJT 工作在放大区。,CE Amp.,放大交流信号 : Vi VBE IB IC VRC VCE,VBE = 0.7V + Vi,IB = IBQ + ib, IC = ICQ + ic, VCE = VCEQ + VRC,放大交流信号 : Vi VBE IB IC VRC VCE Vo,capacitive resistance coupling,地:输入、输出、直流电源公共端; CE:E 接地 有源器件:加直流电源下才可正常工作的器件 有源器件作用:按输入信号规律把直流电源能量转换成交流输出能量,RC Coupling CE Amp
8、lifier (阻容耦合式),Q点:I BQ = (VCC 0.7V)/ RB (Fixed IB biased 固定偏置电路 ) I CQ = I BQ VCC = I CQ RC + V CEQ (DC Load line:Q点的规律),DC.负载线斜率:- 1 / RC (RC :CE 间直流负载),AC.负载线斜率:- 1 / RC | RL (RC | RL :CE 间交流负载),EC,UBEQ,UBE,IBQ,IB,Ui,Q,UBE = UBEQ + Ui,Uo,IB2,IB1,IB1,IB2,IC1,IC2,AC Load line 交流负载线方程 (过Q点) : IC - IC
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 信息与通信 信息与通信Analogue Electronic Principles 信息 通信 Analogue
链接地址:https://www.31doc.com/p-2000479.html