利盈娱乐(中国)创新平台有限公司

线性(xing)调整(zheng)(zheng)器(qi)的(de)(de)主(zhu)要缺陷是(shi)串接(jie)晶(jing)体管(guan)存在过大(da)(da)功耗 。一切(qie)的(de)(de)负载电(dian)(dian)(dian)流(liu)(liu)(liu)都必需经过串接(jie) 晶(jing)体管(guan)，其功耗为 C V卢c -Vo ） 。大(da)(da)多(duo)数(shu)状(zhuang)况下(xia) ，串接(jie) NPN型晶(jing)体管(guan)的(de)(de)最(zui)(zui)小压(ya)(ya)(ya)(ya)差（c-V.）为2.5V。因而(er)，若(ruo)直流(liu)(liu)(liu)输(shu)入(ru)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)由工频变(bian)压(ya)(ya)(ya)(ya)器(qi)次级整(zheng)(zheng)流(liu)(liu)(liu)取得，则(ze)次级臣数(shu)选择应保证交(jiao)流(liu)(liu)(liu)网(wang)(wang)压(ya)(ya)(ya)(ya)最(zui)(zui)低(di)时对(dui)(dui)应的(de)(de)整(zheng)(zheng)流(liu)(liu)(liu)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)为（Vo+2.5)C这(zhei)(zhei)里假定(ding)整(zheng)(zheng)流(liu)(liu)(liu)滤(lv)(lv)波(bo)电(dian)(dian)(dian)容(rong)足够(gou)大(da)(da)，可(ke)疏忽纹波(bo)）。但这(zhei)(zhei)样(yang)做，交(jiao)流(liu)(liu)(liu)网(wang)(wang)压(ya)(ya)(ya)(ya)动(dong)摇(yao)最(zui)(zui)高(gao)时压(ya)(ya)(ya)(ya)差将大(da)(da)很多(duo)，串接(jie)晶(jing)体管(guan)损耗严重(zhong)(zhong)，电(dian)(dian)(dian)源(yuan)效率明(ming)显降(jiang)低(di)。在工频变(bian)压(ya)(ya)(ya)(ya)器(qi)次级整(zheng)(zheng)流(liu)(liu)(liu)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)对(dui)(dui)应网(wang)(wang)压(ya)(ya)(ya)(ya)动(dong)摇(yao)最(zui)(zui)低(di)已有2.sv·压(ya)(ya)(ya)(ya)差的(de)(de)状(zhuang)况下(xia)，这(zhei)(zhei)种网(wang)(wang)压(ya)(ya)(ya)(ya)动(dong)摇(yao)越高(gao)电(dian)(dian)(dian)源(yuan)效率越低(di)的(de)(de)现(xian)象在额定(ding)输(shu)出电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)较低(di)时更为严重(zhong)(zhong) 。以下(xia)三(san)台不(bu)同规格的(de)(de)线性(xing)调整(zheng)(zheng)器(qi)的(de)(de)参数(shu)可(ke)阐明(ming)这(zhei)(zhei)一点，三(san)台调整(zheng)(zheng)器(qi)的(de)(de)输(shu)出分别为SV/IOA、15V/10A和30V/10A。设次级滤(lv)(lv)波(bo)电(dian)(dian)(dian)容(rong)足够(gou)大(da)(da)，输(shu)入(ru)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)绞波(bo)可(ke)疏忽。次级整(zheng)(zheng)流(liu)(liu)(liu)取得的(de)(de)直流(liu)(liu)(liu)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)的(de)(de)动(dong)摇(yao)范围与交(jiao)流(liu)(liu)(liu)网(wang)(wang)压(ya)(ya)(ya)(ya)动(dong)摇(yao)范围对(dui)(dui)应，均为士(shi)15%。若(ruo)网(wang)(wang)压(ya)(ya)(ya)(ya)输(shu)入(ru)最(zui)(zui)低(di)（-15%）时，变(bian)压(ya)(ya)(ya)(ya)器(qi)次级电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)为 （ Vo+2.5 ） ，则(ze)网(wang)(wang)压(ya)(ya)(ya)(ya)输(shu)入(ru)最(zui)(zui)高(gao) （ ＋15%） 时，最(zui)(zui)大(da)(da)直流(liu)(liu)(liu)输(shu)入(ru)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)为 1.30V如(ru)

从上面数据可见(jian) ，直(zhi)流(liu)输出(chu)(chu)电压低时调(diao)整器(qi)(qi)的效率(lv)比输出(chu)(chu)电压高(gao)时低很(hen)多 。若不疏忽(hu)输 入(ru)网压纹波(bo)且允许网压动摇士(shi) 15%，则(ze) 5V 输出(chu)(chu)调(diao)整器(qi)(qi)的效率(lv)只 有 32% 35%。