电流互感器的减极性：即当使一次电流自L1端流向L2。时，二次电流自K1端流出经外部回路到K2。L1和K1，L2和K2分别为同极性端。反之，则为加极性。
Decreasing polarity of current transformer: that is, when the primary current flows from L1 to L2. The secondary current flows from the K1 terminal to the K2 through the external circuit. L1 and K1, L2 and K2 are homopolar ends, respectively. On the contrary, polarity is added.
分析判断：
Analytical judgment:
当开关合上的瞬间，如果表针向正的方向摆，而拉开关的瞬间，表针向负的方向摆动，则接电池正极的端子与接表计正极的端子是同极性的。此时如果它们的标号也同名称（如L1与K1），则此互感器是减极性的，反之，则是加极性端。
When the switch closes, if the needle swings in the positive direction and the needle swings in the negative direction at the moment of pulling the switch, the terminal connecting the positive pole of the battery and the terminal connecting the positive pole of the meter are the same polarity. At this time, if their labels are the same (such as L1 and K1), then the transformer is depolarized, and on the contrary, it is polarized.
电流互感器极性判断直流法：
DC method for judging polarity of current transformer:
用1.5～3V干电池将其正极接于互感器的一次线圈L1，L2接负极，互感器的二次侧K1接毫安表正极，负极接K2，接好线后，将K合上毫安表指针正偏，拉开后毫安表指针负偏，说明互感器接在电池正极上的端头与接在毫安表正端的端头为同极性，即L1、K1为同极性即互感器为减极性。
With 1.5-3V dry battery, its positive pole is connected to the primary coil L1, L2 is connected to the negative pole, the secondary side K1 of the transformer is connected to the positive pole of the niaosu.07858.netshusongjiw.89ix.com wangdian.89ix.comgelishan.89ix.comchengbao.89ix.compentuji.89ix.commilliampere meter, and the negative pole is connected to K2. After wiring, K is connected to the positive deviation of the pointer of the milliampere meter, and the negative deviation of the pointer of the milliampere meter is pulled off. This shows that the end of the transformer connected to the positive pole of the battery is the same polarity as the end of the positive end of the milliampere meter, that is, L1 and K1 are the same polarity, that is the To reduce polarity.