I have a handful of relays that I am working with for a project. I'm familiar with 4 pin relays, where there is a coil and switch,but the relays I am working with have 8 pins.
Here is the model# and data sheet
EC2-5NU https://www.mouser.com/ds/2/212/KEM_R7002_EC2_EE2-1104574.pdf
On page 3 there is a diagram, I have the Non-latch type on the left.
Pins 1&12 are for the coil, but the switch pins are a bit confusing to me.
It looks like 3-4 & 9-10 are normally closed, and 4-5 & 8-8 are normally open.
What is confusing me is why there are two sets of switch pins.
Best Answer
As others have stated it is a dual/double pole relay. That is there are two independent three-way, or dual-throw, switches inside the relay. It is properly named a Double-Pole-Dual-Throw DPDT relay.
If it helps, the diagram below may be easier to understand.
simulate this circuit – Schematic created using CircuitLab
Interestingly they numbered the pins to include the missing pins 2, and 11, and left room to include the second coil on pins 6 and 7 for the dual coil latching type. So in effect it is a 12 pin part. Designing your PCB that way makes changing the style of relay later much easier.