兩(liang)個(ge)(ge)相互(hu)靠(kao)近的(de)導體，中間(jian)夾一層(ceng)不導電(dian)(dian)(dian)(dian)(dian)的(de)絕(jue)緣介質，這就構成了電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)。當電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)的(de)兩(liang)個(ge)(ge)極板之(zhi)間(jian)加上電(dian)(dian)(dian)(dian)(dian)壓時，電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)就會儲存電(dian)(dian)(dian)(dian)(dian)荷。電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)量(liang)在數值上等于一個(ge)(ge)導電(dian)(dian)(dian)(dian)(dian)極板上的(de)電(dian)(dian)(dian)(dian)(dian)荷量(liang)與(yu)兩(liang)個(ge)(ge)極板之(zhi)間(jian)的(de)電(dian)(dian)(dian)(dian)(dian)壓之(zhi)比(bi)。

由(you)于超(chao)級電(dian)容(rong)器(qi)的安全性尚未廣(guang)泛應用于消費電(dian)子領(ling)域，缺(que)乏相應的行業標準(zhun)，與18650等常見鋰離子電(dian)池相比，超(chao)級電(dian)容(rong)器(qi)的安全性更為(wei)(wei)突出。為(wei)(wei)了(le)提高效率，單個超(chao)級電(dian)容(rong)器(qi)的ESR一般為(wei)(wei)mΩ級，這意味著短路(lu)后果非常嚴重（大電(dian)流）會(hui)發生超(chao)溫、爆炸、燃燒(shao)事故，屬于危(wei)險設(she)備。

除電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)器外，通常屬(shu)于弱電(dian)(dian)領域的(de)電(dian)(dian)容(rong)(rong)器是安全的(de)非移動設備(bei)。電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)器的(de)老化(hua)會導致(zhi)鼓頂(ding)和(he)爆裂(lie)，導致(zhi)電(dian)(dian)路板等電(dian)(dian)器故障(zhang)或損壞。

電容器，通常簡稱其(qi)容納電荷的能力是電容，用(yong)字母(mu)C表示。

定義(yi)1：顧名思義(yi)，電(dian)(dian)容(rong)器是(shi)一種(zhong)安裝(zhuang)電(dian)(dian)容(rong)器，是(shi)一種(zhong)容(rong)納電(dian)(dian)荷的(de)設備。英(ying)文名稱：capacitor。電(dian)(dian)容(rong)器是(shi)電(dian)(dian)子(zi)設備中(zhong)廣泛使用的(de)電(dian)(dian)子(zi)元件之一。廣泛應用于電(dian)(dian)路中(zhong)的(de)隔直通交、耦合、旁路、濾波、調諧電(dian)(dian)路、能量轉換、控制等(deng)。

定義2：電容器，任何兩個絕緣且(qie)相(xiang)距很近的導體(包括導線)之間都形成一個電容器。