I'm trying to power a Emlid RTK gps through its DFS connector. There is a GND pin and a 5V pin. I'm going to connect the 5V to '+' on my power supply but what do I connect the GND to? GND or '-' on my power supply? My power supply has the following 3 knobs:


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  • \$\begingroup\$ And what else is connected to this thing? \$\endgroup\$
    – Matt Young
    Commented Dec 20, 2017 at 3:12
  • 1
    \$\begingroup\$ I'm pretty sure that the GND and "-" pins on your power supply are internally shorted, check it out with a multimeter. \$\endgroup\$
    – Ron Beyer
    Commented Dec 20, 2017 at 3:21
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    \$\begingroup\$ @RonBeyer Doubtful. Usually the DC output is isolated, and the GND pin is provided for when earth reference is required. Connecting the two grounds willy nilly could result in nothing happening, or magic smoke escaping. \$\endgroup\$
    – Matt Young
    Commented Dec 20, 2017 at 3:45
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    \$\begingroup\$ @MattYoung Magic smoke followed by my boss's wrath \$\endgroup\$
    – Lightsout
    Commented Dec 21, 2017 at 1:41

1 Answer 1


You should connect the GND pin of your GPS module to the '-' pin of your power supply. The '+' and the '-' pins on the power supply are designed to be the outputs of the supply. The GND pin on the supply is completely isolated from '+' and '-', and is connected to Earth, literally. It exists as a safety precaution, in case the electronics inside the power supply's casing somehow comes in contact with the casing itself, it can be shorted to the Earth, and not shock the person using it.

Explained here to: https://www.eevblog.com/forum/beginners/bench-power-supply-confusion/

  • 2
    \$\begingroup\$ @KingDuken, I'm not sure you read his answer correctly. No where does he say the "-" terminal on the power supply is the same thing as the GND terminal. \$\endgroup\$
    – Dan Laks
    Commented Dec 20, 2017 at 5:32
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    \$\begingroup\$ @KingDuken This answer doesn't say anything about "-" and GND being the same thing.... \$\endgroup\$
    – MCG
    Commented Dec 20, 2017 at 10:44
  • \$\begingroup\$ Unfortunatly i had a poopoo power supply, the current stayd at 0 for some reason after i connected so it didnt work anyways... \$\endgroup\$
    – Lightsout
    Commented Dec 21, 2017 at 1:40

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