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Relay Coil has Polarity?

Part# NA12W-K
Datasheet= Taydel Electronics
Why does this have a polarity? I like it because its small and this version is a SPDT. I use it to trigger a larger relay coil and illuminate an LED as shown in this schematic.
Im concerned because the datasheet has no mention of it.
 

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Inquisitive

Super Moderator
Is the coil marked as 12VDC in the datasheet?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Why does this have a polarity? I like it because its small and this version is a SPDT. I use it to trigger a larger relay coil and illuminate an LED as shown in this schematic.
Im concerned because the datasheet has no mention of it.
Some relays have a diode built-in across the coil, in which case it MUST be wired the correct way. I suspect the PCB is designed to optionally use that kind of relay.
 

shortbus=

Well-Known Member
Most Helpful Member
Why does this have a polarity?
Do you mean the voltages shown in the data sheet as, "must operate" or "must release"? If so those are just the voltages that are used to meet the standards, meaning they won't work in a circuit that uses a negative voltage.

Noe some car relays are polarity dependent on the coils. They have a built in diode to protect the rest of the circuit when shutting off. But these don't seem to have that in them.

Looks like I type too slow.:)
 

eTech

Well-Known Member
Part# NA12W-K
Datasheet= Taydel Electronics
Why does this have a polarity? I like it because its small and this version is a SPDT. I use it to trigger a larger relay coil and illuminate an LED as shown in this schematic.
Im concerned because the datasheet has no mention of it.
The datasheet schematic diagram has polarity markings because it is intended to represent both a standard relay coil (that isn't polarity sensitive) and a single coil latching relay (that IS polarity sensitive). The part number you've supplied is a standard 12VDC relay.
 
The part number you've supplied is a standard 12VDC relay.
i see now that the data sheet represents ALL of the series for this relay. I do however have 3 of NA12WK and these are polarity sensitive. At the bottom of the document (pinout area) it "shows" both NA and NAL (latching) are both polarity sensitive. Awesome information. thank you.
 

AnalogKid

Well-Known Member
Most Helpful Member
I zipped through the datasheet, and did not see any mention of a suppression diode option. However, there are two different latching versions, and those are polarity sensitive. The bottom of the relay has markings molded in for all variations; the + and - markings do not apply to the non-latching versions.

ak
 

eTech

Well-Known Member
i see now that the data sheet represents ALL of the series for this relay. I do however have 3 of NA12WK and these are polarity sensitive. At the bottom of the document (pinout area) it "shows" both NA and NAL (latching) are both polarity sensitive. Awesome information. thank you.
The NA12WK IS NOT polarity sensitive. Only the latching type relays (NAL) of this NA series are polarity sensitive.

BTW- The datasheet does not indicate that any of these relays are available with a diode.
 

Lo_volt

New Member
I'd suggest following the polarity in the data sheet, even if you don't have a latching unit. I've been stung by such a relay in the past. I don't recall the model, it was a simple SPST unit but it was polarity sensitive and would not work at all with polarity reversed.
 

AnalogKid

Well-Known Member
Most Helpful Member
I'd suggest following the polarity in the data sheet, even if you don't have a latching unit. I've been stung by such a relay in the past. I don't recall the model, it was a simple SPST unit but it was polarity sensitive and would not work at all with polarity reversed.
Non-latching and polarity-sensitive probably means it had an internal suppression diode.

ak
 

Lo_volt

New Member
Non-latching and polarity-sensitive probably means it had an internal suppression diode.
This was 25 years ago and the result of my naivety. Hopefully the TS learns from my mistake and doesn't fab a board with the relay miswired. That's what I did. Fortunately it was a prototype and was corrected before we went into production.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
I'd suggest following the polarity in the data sheet, even if you don't have a latching unit. I've been stung by such a relay in the past.
A good idea.

Some low power non-latching relays use a permanent magnet "assist" to reduce the operating power, which means the coil polarity must be correct to interact with that.
 

Diver300

Well-Known Member
Most Helpful Member
Probably not the case here, but some relays have an LED to show that they are activated. That LED may only work one way even if the relay doesn't mind.

One 12 V plug-in relay that I used had an LED that was actually two LEDs in parallel, in opposite polarities, to get over that issue.
 
The NA12WK IS NOT polarity sensitive.
This is why i created this post. I was thinking the datasheet is wrong or ive got faulty parts. But i will confirm that when i hook this up to 12V it will not trigger the coil unless i have the positive lead connected to pin one.
 
I suggest testing the relay and not assume anything...
Thats what I did. Despite what the datasheet says the coil is polarity sensitive. I did a lot of searching before i created the post and I could not confirm (on paper) that this NA12w was polarity sensitive but here we are. 20210623_150207.jpg
 
So all you need is a latch pulse to retain and a unlatch pulse of opposite polarity to release.
Im a bit new to this but Im finding a good deal of incorrect information (pinouts, voltage, polarity) on some parts. For example in "design spark" the polarity of a PCB image on an LED was reversed. And I kinda dont trust anything but thats just me.
 

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