一、三極管符號是什么
三極管的文(wen)字符號國外一(yi)般(ban)用宇母QR或(huo)(huo)Q表示(shi)，在國內一(yi)般(ban)用VT或(huo)(huo)V表示(shi)。
此外三極管參(can)數中(zhong)文字符(fu)號英文對照：
1、Pcm集電極最大耗散功率。
2、Icm集電(dian)極最大允許電(dian)流。
3、V（br）cbo發(fa)射極(ji)開路時(shi)，集電極(ji)與基極(ji)間反(fan)向擊穿(chuan)電壓。
4、V（br）ceo基極(ji)開(kai)路時，集電極(ji)與發射極(ji)間反(fan)向擊穿電壓。
5、V（br）ebo集電極(ji)開路時(shi)，發射極(ji)與基極(ji)間反向擊穿電壓。
6、Icbo發射極(ji)(ji)開路時，集電(dian)極(ji)(ji)與(yu)基極(ji)(ji)間反向漏電(dian)流。
二、三極管放大電路放大的是電流還是電壓
三極管是一個電流控制元件，其可以通過小電流來控制大電流，所以三極管是電流放大器件。
要使(shi)三(san)極(ji)(ji)(ji)(ji)管(guan)處(chu)于放大狀(zhuang)態，其(qi)基(ji)(ji)極(ji)(ji)(ji)(ji)電流(liu)必須大于零(ling)且小于飽和電流(liu)。例如(ru)鍺材(cai)料(liao)的(de)三(san)極(ji)(ji)(ji)(ji)管(guan)，它處(chu)于放大狀(zhuang)態時(shi)，集電極(ji)(ji)(ji)(ji)與(yu)發射(she)極(ji)(ji)(ji)(ji)之間的(de)電壓大于1，基(ji)(ji)極(ji)(ji)(ji)(ji)與(yu)發射(she)極(ji)(ji)(ji)(ji)之間電壓大于零(ling)，基(ji)(ji)極(ji)(ji)(ji)(ji)與(yu)集電極(ji)(ji)(ji)(ji)之間電壓小于零(ling)。也就是說，鍺材(cai)料(liao)的(de)三(san)極(ji)(ji)(ji)(ji)管(guan)處(chu)于放大狀(zhuang)態時(shi)，其(qi)發射(she)結(jie)正偏，反射(she)結(jie)反偏。
三極(ji)(ji)(ji)(ji)(ji)(ji)管處于放大狀態時，其(qi)基(ji)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)與(yu)集(ji)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)之間有唯一的(de)對應關系，即基(ji)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)增加(jia)，集(ji)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)也隨之增加(jia)。所以，三極(ji)(ji)(ji)(ji)(ji)(ji)管的(de)集(ji)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)主要(yao)受其(qi)基(ji)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)控制變(bian)(bian)(bian)化，而(er)且(qie)集(ji)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)的(de)變(bian)(bian)(bian)化比其(qi)基(ji)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)流(liu)變(bian)(bian)(bian)化大的(de)多。
所以說(shuo)，三極(ji)管的(de)是電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)放大器件(jian)。把(ba)基(ji)(ji)(ji)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)流(liu)(liu)(liu)向發(fa)射(she)極(ji)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)叫(jiao)基(ji)(ji)(ji)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)，把(ba)集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)流(liu)(liu)(liu)向發(fa)射(she)極(ji)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)叫(jiao)集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。三極(ji)管的(de)放大作用就是集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)受基(ji)(ji)(ji)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)控制(zhi)并且是基(ji)(ji)(ji)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)變(bian)化很小，就引起集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)很大變(bian)化，且滿足一定的(de)比例關(guan)系。
