polarityn.极性;磁性引力;两极
polarity of feedback loop反馈环的极性
polarity of feedback link反馈链的极性
polarity telegraph system极性电报制
polarity directional relay极化方向继电器
polarity of picture signal[电] 图像讯号的极性
polarity of electric field电场极性
polarity-reversing switch极性转换开关
polarity inverting amplifier极性反转放大器,倒相放大器