如果(guo)晶體管的(de)共發射(she)極(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)流放大系(xi)數β = IC / IB =100, 集電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)流 IC= β*IB=10mA。在(zai)500Ω的(de)集電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)負載電(dian)(dian)(dian)(dian)(dian)阻上(shang)有(you)電(dian)(dian)(dian)(dian)(dian)壓降VRC=10mA*500Ω=5V，而晶體管集電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)和發射(she)極(ji)(ji)(ji)(ji)(ji)之(zhi)間(jian)的(de)壓降為VCE=5V，如果(guo)在(zai)基極(ji)(ji)(ji)(ji)(ji)偏置電(dian)(dian)(dian)(dian)(dian)路中(zhong)(zhong)疊加一個(ge)交(jiao)變的(de)小電(dian)(dian)(dian)(dian)(dian)流ib，在(zai)集電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)路中(zhong)(zhong)將出現一個(ge)相(xiang)應的(de)交(jiao)變電(dian)(dian)(dian)(dian)(dian)流ic，有(you)c/ib=β，實現了雙極(ji)(ji)(ji)(ji)(ji)晶體管的(de)電(dian)(dian)(dian)(dian)(dian)流放大作用。

金屬氧(yang)化物(wu)半導(dao)體(ti)場(chang)效應三極(ji)管(guan)的(de)(de)基本工(gong)作原(yuan)理是靠(kao)半導(dao)體(ti)表(biao)面(mian)的(de)(de)電(dian)(dian)(dian)(dian)(dian)場(chang)效應，在半導(dao)體(ti)中感生出導(dao)電(dian)(dian)(dian)(dian)(dian)溝道(dao)來進行工(gong)作的(de)(de)。當(dang)柵 G 電(dian)(dian)(dian)(dian)(dian)壓 VG 增大時(shi)(shi)， p 型(xing)半導(dao)體(ti)表(biao)面(mian)的(de)(de)多數載流(liu)子(zi)棗空穴逐漸減少、耗盡，而電(dian)(dian)(dian)(dian)(dian)子(zi)逐漸積累到反型(xing)。當(dang)表(biao)面(mian)達(da)到反型(xing)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)子(zi)積累層(ceng)(ceng)將(jiang)(jiang)在 n+ 源(yuan)區 S 和 n+ 漏區 D 之間(jian)形(xing)成導(dao)電(dian)(dian)(dian)(dian)(dian)溝道(dao)。當(dang) VDS ≠ 0 時(shi)(shi)，源(yuan)漏電(dian)(dian)(dian)(dian)(dian)極(ji)之間(jian)有較(jiao)大的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu) IDS 流(liu)過。使半導(dao)體(ti)表(biao)面(mian)達(da)到強反型(xing)時(shi)(shi)所需(xu)加(jia)的(de)(de)柵源(yuan)電(dian)(dian)(dian)(dian)(dian)壓稱(cheng)為閾值電(dian)(dian)(dian)(dian)(dian)壓 VT 。當(dang) VGS>VT 并(bing)取不(bu)同數值時(shi)(shi)，反型(xing)層(ceng)(ceng)的(de)(de)導(dao)電(dian)(dian)(dian)(dian)(dian)能力將(jiang)(jiang)改變，在相同的(de)(de) VDS 下也將(jiang)(jiang)產(chan)生不(bu)同的(de)(de) IDS , 實現柵源(yuan)電(dian)(dian)(dian)(dian)(dian)壓 VGS 對源(yuan)漏電(dian)(dian)(dian)(dian)(dian)流(liu) IDS 的(de)(de)控(kong)制。