電(dian)火(huo)花(hua)和熱效應(ying)是(shi)引(yin)起(qi)爆(bao)炸(zha)性危(wei)險(xian)(xian)(xian)氣(qi)體(ti)爆(bao)炸(zha)的(de)(de)(de)主要(yao)點燃(ran)源(yuan)，本安(an)就是(shi)通過限制電(dian)火(huo)花(hua)和熱效應(ying)兩(liang)個可(ke)(ke)能(neng)(neng)(neng)的(de)(de)(de)點燃(ran)源(yuan)的(de)(de)(de)能(neng)(neng)(neng)量來實現的(de)(de)(de)。在(zai)正(zheng)(zheng)常工(gong)(gong)作和故障狀態下當儀(yi)(yi)表(biao)可(ke)(ke)能(neng)(neng)(neng)產(chan)生的(de)(de)(de)電(dian)火(huo)花(hua)或(huo)熱效應(ying)的(de)(de)(de)能(neng)(neng)(neng)量小(xiao)于這個能(neng)(neng)(neng)量時(shi)，儀(yi)(yi)表(biao)不可(ke)(ke)能(neng)(neng)(neng)點燃(ran)爆(bao)炸(zha)性危(wei)險(xian)(xian)(xian)氣(qi)體(ti)而產(chan)生爆(bao)炸(zha)。原理是(shi)從限制能(neng)(neng)(neng)量入手，可(ke)(ke)靠(kao)地將電(dian)路中的(de)(de)(de)電(dian)壓(ya)和電(dian)流限制在(zai)一個允許的(de)(de)(de)范圍(wei)(wei)內，以保證儀(yi)(yi)表(biao)在(zai)正(zheng)(zheng)常工(gong)(gong)作或(huo)發(fa)生短接和元器件損壞等故障情況下產(chan)生的(de)(de)(de)電(dian)火(huo)花(hua)和熱效應(ying)不致于引(yin)起(qi)其周圍(wei)(wei)可(ke)(ke)能(neng)(neng)(neng)存(cun)在(zai)的(de)(de)(de)危(wei)險(xian)(xian)(xian)氣(qi)體(ti)的(de)(de)(de)爆(bao)炸(zha)。