What is the difference between a polarized relay and a non-polarized relay?

Polarized relay (polarized relay) DC polarized relay. Referred to as a pole relay. This relay has the function of reflecting the direction of the external input signal electrode (positive and negative). Main features: ① There are permanent magnets or local coils acting as permanent magnets in the magnetic circuit structure of the relay. ②The armature action of the relay is controlled by two independent magnetic systems: one is controlled by the electromagnetic system generated by the input coil current, and the magnetic flux it generates is called the control flux φk; the other is controlled by the permanent magnet system generated by the permanent magnet. The resulting magnetic flux is called polarized magnetic flux φj. ③High sensitivity, the poled relay can operate with less ampere-turn value. For example: some action ampere-turns are 1 to 4, while stepless relays generally require 50-200 ampere-turns. ④The action time is faster, the fastest poled relay only needs 1~2ms, or even less. Infinite relays need 10 to 100ms, and some large relays have a slower action time. Types There are various structural forms of organic relays. Generally classified according to the magnetic circuit structure, they can be divided into three types: series type, parallel type (or differential type) and bridge type.