1. Rated working voltage: refers to the voltage required by the coil when the relay is working normally. Depending on the model of the relay, it can be either AC voltage or DC voltage.

2. DC resistance: refers to the DC resistance of the coil in the relay, which can be measured by a multimeter.
3. Pick-up current: It refers to the minimum current that the relay can generate the pick-up action. In normal use, the given current must be slightly larger than the pull-in current, so that the relay can work stably. For the working voltage applied to the coil, generally do not exceed 1.5 times the rated working voltage, otherwise a large current will be generated and the coil will be burned.
4. Release current: It refers to the maximum current that the relay produces to release. When the current in the pull-in state of the relay is reduced to a certain extent, the relay will return to the unenergized release state. The current at this time is much smaller than the pull-in current.
5. Contact switching voltage and current: refers to the voltage and current that the relay is allowed to load. It determines the magnitude of the voltage and current that the relay can control. It cannot exceed this value when using it, otherwise it is easy to damage the contacts of the relay.