A.當(dāng)熔斷器兩斷電壓大于200mA時(shí),認(rèn)為熔斷器已壞; B.當(dāng)熔斷器兩斷電壓小于200mA時(shí),認(rèn)為熔斷器已壞; C.當(dāng)與負(fù)載相連的光偶三極管導(dǎo)通時(shí),認(rèn)為熔斷器已壞; D.當(dāng)與負(fù)載相連的光偶三極管不導(dǎo)通時(shí),認(rèn)為熔斷器已壞;
A.負(fù)載電流的1.5至2倍; B.負(fù)載電流的2到3倍; C.負(fù)載電流的3到5倍;