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Latching relays circuit

Discussion in 'Automotive Electronics' started by UKenGB, Apr 9, 2018.

  1. UKenGB

    UKenGB New Member

    Apr 9, 2018
    Voltage requirements of relay coil can be allowed for, as explained. I'm not concerned about safety implications. Most modern vehicles have headlights switched by relays that are held on to produce the light and any failure to hold on the relay will cause a 'lights out' problem. Anything can of course fail, but I don't see this as being any more prone to that than current vehicle design practices.
  2. Gaudeamos

    Gaudeamos New Member

    Mar 23, 2018
    British Columbia
    Yes, modern vehicles' headlights are switched through relays, but the headlight on/off state is retained by a mechanical (usually rotary) switch and/or the vehicle's ECU.
    Critical electronic control components (like ECU) are protected from failing and resetting due to brownout conditions (like cold cranking).
    A momentary relay failure due to brownout may cause the headlights to turn off momentarily, but they'll recover to their 'on' state once the brownout has passed.
    That's not the case with the all-relay circuit we're discussing.

    In any event, I hope the flip flop module that you intend to use will fit your needs.

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