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  • DC relay coil

    From Bob Engelhardt@21:1/5 to All on Tue Oct 19 11:08:26 2021
    I have a DC relay with the coil connections marked "+" & "-". Does it
    matter? The relay operates with either polarity so there is no internal flyback diode. It's a 24v, 33ma coil for those who want to know.

    Thanks, Bob

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  • From Tom Biasi@21:1/5 to Bob Engelhardt on Tue Oct 19 11:23:36 2021
    On 10/19/2021 11:08 AM, Bob Engelhardt wrote:
    I have a DC relay with the coil connections marked "+" & "-".  Does it matter?  The relay operates with either polarity so there is no internal flyback diode.  It's a 24v, 33ma coil for those who want to know.

    Thanks, Bob
    If the designers marked it, probably would be good to follow that.

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  • From Bob Engelhardt@21:1/5 to All on Tue Oct 19 15:33:58 2021
    Yeah ... I guess what I was really wondering was why they would do that.

    If the designers marked it, probably would be good to follow that.

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  • From Sjouke Burry@21:1/5 to Bob Engelhardt on Tue Oct 19 22:26:29 2021
    On 19.10.21 21:33, Bob Engelhardt wrote:
    Yeah ... I guess what I was really wondering was why they would do that.

    If the designers marked it, probably would be good to follow that.

    they should do that if a built-in diode is present.
    Also, the plus and minus identify the coil pins.

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  • From Tom Biasi@21:1/5 to Sjouke Burry on Tue Oct 19 16:31:40 2021
    On 10/19/2021 4:26 PM, Sjouke Burry wrote:
    On 19.10.21 21:33, Bob Engelhardt wrote:
    Yeah  ... I guess what I was really wondering was why they would do that. >>
    If the designers marked it, probably would be good to follow that.

    they should do that if a built-in diode is present.
    Also, the plus and minus identify the coil pins.

    They may use that package to make units with the diode.

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  • From Bob Engelhardt@21:1/5 to All on Thu Oct 21 09:55:07 2021
    I Googled it (like I should have in the first place). There are a
    couple of reasons that a DC relay may be polarized:
    - internal flyback diode (as mentioned)
    - an internal LED indicator
    - a permanent magnet used to augment the mag field
    - in a latching relay

    My relay does have a LED indicator, so that's what I'm assuming is the
    reason for my polarization. And not a permanent magnet.

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