當在通電(dian)(dian)螺線(xian)(xian)管內部(bu)插入鐵(tie)(tie)芯(xin)后，鐵(tie)(tie)芯(xin)被通電(dian)(dian)螺線(xian)(xian)管的(de)(de)磁(ci)(ci)(ci)(ci)(ci)場磁(ci)(ci)(ci)(ci)(ci)化。磁(ci)(ci)(ci)(ci)(ci)化后的(de)(de)鐵(tie)(tie)芯(xin)也變(bian)(bian)成了一個(ge)磁(ci)(ci)(ci)(ci)(ci)體，這(zhe)樣(yang)由(you)于(yu)兩(liang)個(ge)磁(ci)(ci)(ci)(ci)(ci)場互相(xiang)疊加，從而(er)使(shi)螺線(xian)(xian)管的(de)(de)磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)大大增強。電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)是(shi)可(ke)(ke)以(yi)(yi)通電(dian)(dian)流(liu)(liu)來(lai)產生磁(ci)(ci)(ci)(ci)(ci)力的(de)(de)器(qi)件，屬非磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)，可(ke)(ke)以(yi)(yi)很容易地將其磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)啟動或是(shi)消除。電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)有許多優(you)點：電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)的(de)(de)磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)有無可(ke)(ke)以(yi)(yi)用通、斷電(dian)(dian)流(liu)(liu)控(kong)制(zhi)；磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)的(de)(de)大小(xiao)可(ke)(ke)以(yi)(yi)用電(dian)(dian)流(liu)(liu)的(de)(de)強弱或線(xian)(xian)圈的(de)(de)匝(za)數多少來(lai)控(kong)制(zhi)；也可(ke)(ke)通過改變(bian)(bian)電(dian)(dian)阻控(kong)制(zhi)電(dian)(dian)流(liu)(liu)大小(xiao)來(lai)控(kong)制(zhi)磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)大小(xiao)；它的(de)(de)磁(ci)(ci)(ci)(ci)(ci)極可(ke)(ke)以(yi)(yi)由(you)改變(bian)(bian)電(dian)(dian)流(liu)(liu)的(de)(de)方向來(lai)控(kong)制(zhi)，等等。即：磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)的(de)(de)強弱可(ke)(ke)以(yi)(yi)改變(bian)(bian)、磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)的(de)(de)有無可(ke)(ke)以(yi)(yi)控(kong)制(zhi)、磁(ci)(ci)(ci)(ci)(ci)極的(de)(de)方向可(ke)(ke)以(yi)(yi)改變(bian)(bian)，磁(ci)(ci)(ci)(ci)(ci)性(xing)(xing)可(ke)(ke)因電(dian)(dian)流(liu)(liu)的(de)(de)消失而(er)消失。