吉林师范大学信息技术学院《模拟电子技术》课件：模拟电子电路基础1.2.2.ppt

1 §1.4 双极型晶体三极管(BJT) 1.4 .1 BJT的工作原理 结构： 由两个PN结和三个电极构成。 有两个基本类型： NPN型 PNP型 3．BJT的偏置方式： ①发射结正偏、集电结反偏，BJT处于放大状态 ②发射结反偏、集电结正偏，BJT处于反向应用状态，（一般不宜 反向应用） ③二个PN结均正偏，晶体管处于饱合状态 ④二个PN结均反偏，晶体管处于截至状态 4、 BJT三种基本组态 共基极(CB) 组态 , 共射极(CE) 组态 , 共集电极(CC) 组态 * * 1.4 .1 BJT的工作原理 1. 4 . 2 BJT的静态特性曲线 1. 4. 3 BJT的主要参数 返回 1. 4. 3 BJT的小信号模型 集电区 基区 发射区 基 区（B）区：薄、低渗杂 三个电极： 发射极（Emitter）:E(e) 基 极（Base） :B(b) 集电极（Collctor）:C 集电区（C）区：渗杂适中 E 发射极 B 基极 C 集电极 发射结 集电结 1．NPN 型 三个区域： 发射区（E区）：高渗杂 两个PN结： 发射结（BE结） 集电结（CB结） E 发射极 B 基极 C 集电极 发射结 集电结 N P N+ 2. PNP型 N P P+ 返回 集电区 基区 发射区 E 发射极 B 基极 C 集电极 发射结 集电结 N P N+ E 发射极 B 基极 C 集电极 发射结 集电结 N P P+ 返回 返回 EC EB EB EC RC b Rb c e ● ● ● ● 一 BJT的工作原理 1. 载流子的传输过程： 将NPN BJT接成共射极型：以射极为输入和输出回路的公共端 即： uBEUT , 发射结正偏 → 易于E区多子扩散 uCB＞0 ， 集中结反偏 → 易于B区少子漂移 b c e iE iB iC iEP ib1 icn1 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ien iC iE iB ien= icn1 + ib1 iE = ien + iEP ≈ ien ICBO= icn2 + icp iE iE iE iE iC iC iC iC iB iB iB iB iC= ICBO + icn1 ; iB= ib1 + iEP -ICBO icn2 icp 返回 (1) 多子通过EB(发射)结注入B区 EB EC RC b Rb c e iEP ib1 icn1 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ien iE iE iE 返回 (2) 由浓度差引起基区非平衡少数载流子的扩散与复合。 EB EC RC b Rb c e ib1 icn1 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ien 返回 EB EC RC b Rb c e ● ● ● ● iEP ib1 icn1 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●