Relay Current Direction

[Phrazemaster]

Hi, I have a question about a relay I'm using. I wonder if it matters which way I hook up the current. It's not clear to me from the datasheet if there is a tamping diode; there is just a tiny picture that shows the current direction and no mention of anything else. For the circuit board I am building, it would be a lot easier if the current could flow the other way (just due to spacing/layout). If I'm understanding the datasheet correctly, it's specifying pin 1 hot (+).

Can any eyes better than mine sus out this datasheet and tell if it really matters if I hook it up the way the datasheet shows?

The relay in question is the TQ2-12v, standard relay, digikey part 255-1002-5-ND.

Thanks in advance for any wisdom on this.

Mike

 

[AMZ-FX]

The TQ2-12v is a single side stable relay. In the de-energized condition, the relay contacts are in the position shown on the datasheet. When you put a DC voltage on the relay coil with the polarity shown on the datasheet, it energizes and the contacts flip to the opposite position. Remove the voltage and the contacts return to the de-energized position.

You should add a diode (like a 1N4001) across the relay coil with the cathode going to the + and the anode to the -.

regards, Jack

 

[Phrazemaster]

Thank-you. I do have a diode in the plans for the board. I will make the polarity as the datasheet indicates, just in case.

However, it's just an electromagnet, and unless there is some kind of internal tamping diode, which is not mentioned in the datasheet, it shouldn't matter which direction the current flows. My thinking.

Thanks.

Mike

 

[Dan Kennedy]

It does matter on the TQ series. I'm not sure why, but if you hook them up backwards they
won't pull in. There may be a small magnet as part of the armature which would then imply
a corresponding dc polaarity.

I haven't dissected one, just know they don't work backwards.

 

[Phrazemaster]

Excellent info; thanks!

 

[Phrazemaster]

I actually do have one more quick question. From the datasheet, it appears that pin 1 is the upper right corner of the relay. I say appears to be, because it does not show the actual relay very closely; only it shows the small wiring diagram.

Can anyone verify if the TQ series pin 1's are in the upper right corner of the relay?

Thank-you,

Mike