Power Supply - Shorting a cable creates a ground?

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2
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I used a power supply the other day to power an op-amp. I was told to set it up in the following configuration, however I do not completely understand the why this works.
The shorted cable acts as ground??



enter image description here







share|improve this question
















  • 3




    Who or what told you that?
    – Long Pham
    Aug 29 at 5:14






  • 2




    Does it have isolated outputs and you've been instructed to connect them in series to produce a center tap? It's clear you've connected the + from 1 to the - on the other, but what are you depicting with the black lines at the bottom?
    – K H
    Aug 29 at 5:27






  • 2




    Just to make it clear - the left + isn't shorted to the left -, and the right + isn't shorted to the right -, but the right + is shorted to the left -. I assume the black lines indicate connectors, not shorts.
    – immibis
    Aug 29 at 5:27







  • 1




    Related: electronics.stackexchange.com/questions/392660/….
    – Transistor
    Aug 29 at 6:06










  • Watch out for limitations on how high you can float the individual power supplies. Check the manual.
    – Jon Custer
    Aug 29 at 22:31
















up vote
2
down vote

favorite












I used a power supply the other day to power an op-amp. I was told to set it up in the following configuration, however I do not completely understand the why this works.
The shorted cable acts as ground??



enter image description here







share|improve this question
















  • 3




    Who or what told you that?
    – Long Pham
    Aug 29 at 5:14






  • 2




    Does it have isolated outputs and you've been instructed to connect them in series to produce a center tap? It's clear you've connected the + from 1 to the - on the other, but what are you depicting with the black lines at the bottom?
    – K H
    Aug 29 at 5:27






  • 2




    Just to make it clear - the left + isn't shorted to the left -, and the right + isn't shorted to the right -, but the right + is shorted to the left -. I assume the black lines indicate connectors, not shorts.
    – immibis
    Aug 29 at 5:27







  • 1




    Related: electronics.stackexchange.com/questions/392660/….
    – Transistor
    Aug 29 at 6:06










  • Watch out for limitations on how high you can float the individual power supplies. Check the manual.
    – Jon Custer
    Aug 29 at 22:31












up vote
2
down vote

favorite









up vote
2
down vote

favorite











I used a power supply the other day to power an op-amp. I was told to set it up in the following configuration, however I do not completely understand the why this works.
The shorted cable acts as ground??



enter image description here







share|improve this question












I used a power supply the other day to power an op-amp. I was told to set it up in the following configuration, however I do not completely understand the why this works.
The shorted cable acts as ground??



enter image description here









share|improve this question











share|improve this question




share|improve this question










asked Aug 29 at 5:12









Roo

15617




15617







  • 3




    Who or what told you that?
    – Long Pham
    Aug 29 at 5:14






  • 2




    Does it have isolated outputs and you've been instructed to connect them in series to produce a center tap? It's clear you've connected the + from 1 to the - on the other, but what are you depicting with the black lines at the bottom?
    – K H
    Aug 29 at 5:27






  • 2




    Just to make it clear - the left + isn't shorted to the left -, and the right + isn't shorted to the right -, but the right + is shorted to the left -. I assume the black lines indicate connectors, not shorts.
    – immibis
    Aug 29 at 5:27







  • 1




    Related: electronics.stackexchange.com/questions/392660/….
    – Transistor
    Aug 29 at 6:06










  • Watch out for limitations on how high you can float the individual power supplies. Check the manual.
    – Jon Custer
    Aug 29 at 22:31












  • 3




    Who or what told you that?
    – Long Pham
    Aug 29 at 5:14






  • 2




    Does it have isolated outputs and you've been instructed to connect them in series to produce a center tap? It's clear you've connected the + from 1 to the - on the other, but what are you depicting with the black lines at the bottom?
    – K H
    Aug 29 at 5:27






  • 2




    Just to make it clear - the left + isn't shorted to the left -, and the right + isn't shorted to the right -, but the right + is shorted to the left -. I assume the black lines indicate connectors, not shorts.
    – immibis
    Aug 29 at 5:27







  • 1




    Related: electronics.stackexchange.com/questions/392660/….
    – Transistor
    Aug 29 at 6:06










  • Watch out for limitations on how high you can float the individual power supplies. Check the manual.
    – Jon Custer
    Aug 29 at 22:31







3




3




Who or what told you that?
– Long Pham
Aug 29 at 5:14




Who or what told you that?
– Long Pham
Aug 29 at 5:14




2




2




Does it have isolated outputs and you've been instructed to connect them in series to produce a center tap? It's clear you've connected the + from 1 to the - on the other, but what are you depicting with the black lines at the bottom?
– K H
Aug 29 at 5:27




Does it have isolated outputs and you've been instructed to connect them in series to produce a center tap? It's clear you've connected the + from 1 to the - on the other, but what are you depicting with the black lines at the bottom?
– K H
Aug 29 at 5:27




2




2




Just to make it clear - the left + isn't shorted to the left -, and the right + isn't shorted to the right -, but the right + is shorted to the left -. I assume the black lines indicate connectors, not shorts.
– immibis
Aug 29 at 5:27





Just to make it clear - the left + isn't shorted to the left -, and the right + isn't shorted to the right -, but the right + is shorted to the left -. I assume the black lines indicate connectors, not shorts.
– immibis
Aug 29 at 5:27





1




1




Related: electronics.stackexchange.com/questions/392660/….
– Transistor
Aug 29 at 6:06




Related: electronics.stackexchange.com/questions/392660/….
– Transistor
Aug 29 at 6:06












Watch out for limitations on how high you can float the individual power supplies. Check the manual.
– Jon Custer
Aug 29 at 22:31




Watch out for limitations on how high you can float the individual power supplies. Check the manual.
– Jon Custer
Aug 29 at 22:31










4 Answers
4






active

oldest

votes

















up vote
23
down vote



accepted










You can pick anything you want and call it ground.



This power supply box has two power supplies in it.
Shorting the + of one to the - of the other puts the two power supplies in series. That gives you a so-called "split" power supply.



You can call the middle connection ground and then you have +15V, 0V and -15V wires.



Or you can call the right connection ground, and then you have +30V, +15V and 0V wires.



Or you can call the left connection ground, and you get 0V, -15V and -30V wires.



Note - some dual power supplies have the - of both supplies connected, inside the box. In that case, shorting the + of one to the - of the other would short out one of the supplies. This one doesn't have them connected.






share|improve this answer


















  • 4




    "Shorting the + of one to the - of the other puts the two power supplies in series" - but only if the two supplies are originally isolated from each other, and don't share a common negative rail.
    – Alnitak
    Aug 29 at 21:15

















up vote
4
down vote













In most electronics, "Ground" is simply the point that we want to call "Zero Volts" - it need not have any relation to Earth (AC Power) Ground.



That power supply appears to have three independent isolated supplies. The red line you show connects two of the supplies in series. If you consider that red line as "zero volts/circuit ground" you will have a positive supply from the left-most terminal, and a negative supply from the fifth terminal.






share|improve this answer



























    up vote
    4
    down vote













    It might be easier to understand if I would just draw a schematic of how
    this supply is configured:





    schematic





    simulate this circuit – Schematic created using CircuitLab



    So: only the port with the green marking and ground symbol is actually connected to earth (assuming you connected the supply properly to mains ground using the mains connector).



    If we ignore V3 (which you're not using in your example) then all outputs are "floating" sources, like batteries they can be used in almost any configuration you like. If you do not connect to earth but combine the supplies (for example to make 60 V by connecting V1 and V2 in series) then that combination is still floating relative to ground.



    In your example, the Earth/ground pin is unconnected so your supply is floating. V1 and V2 are in series but the potential relative to ground is still undefined.






    share|improve this answer






















    • Except, on the DP832, V2(-) and V3(-) are connected.
      – Jeroen3
      Aug 29 at 9:58










    • @Jeroen3 Indeed you're right, I missed that one, updating the schematic.
      – Bimpelrekkie
      Aug 29 at 9:59

















    up vote
    1
    down vote













    0V differential is called a virtual ground as in Op Amp inputs, even though without connections they are high input impedance.



    Any 0V reference can be called "ground" in electronics ( but not earth bonded ground).



    I believe you are referring to when a dual supply has a jumper from V1- to V2+ giving a floating virtual 0V ground reference in between and bipolar outputs.






    share|improve this answer




















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      4 Answers
      4






      active

      oldest

      votes








      4 Answers
      4






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes








      up vote
      23
      down vote



      accepted










      You can pick anything you want and call it ground.



      This power supply box has two power supplies in it.
      Shorting the + of one to the - of the other puts the two power supplies in series. That gives you a so-called "split" power supply.



      You can call the middle connection ground and then you have +15V, 0V and -15V wires.



      Or you can call the right connection ground, and then you have +30V, +15V and 0V wires.



      Or you can call the left connection ground, and you get 0V, -15V and -30V wires.



      Note - some dual power supplies have the - of both supplies connected, inside the box. In that case, shorting the + of one to the - of the other would short out one of the supplies. This one doesn't have them connected.






      share|improve this answer


















      • 4




        "Shorting the + of one to the - of the other puts the two power supplies in series" - but only if the two supplies are originally isolated from each other, and don't share a common negative rail.
        – Alnitak
        Aug 29 at 21:15














      up vote
      23
      down vote



      accepted










      You can pick anything you want and call it ground.



      This power supply box has two power supplies in it.
      Shorting the + of one to the - of the other puts the two power supplies in series. That gives you a so-called "split" power supply.



      You can call the middle connection ground and then you have +15V, 0V and -15V wires.



      Or you can call the right connection ground, and then you have +30V, +15V and 0V wires.



      Or you can call the left connection ground, and you get 0V, -15V and -30V wires.



      Note - some dual power supplies have the - of both supplies connected, inside the box. In that case, shorting the + of one to the - of the other would short out one of the supplies. This one doesn't have them connected.






      share|improve this answer


















      • 4




        "Shorting the + of one to the - of the other puts the two power supplies in series" - but only if the two supplies are originally isolated from each other, and don't share a common negative rail.
        – Alnitak
        Aug 29 at 21:15












      up vote
      23
      down vote



      accepted







      up vote
      23
      down vote



      accepted






      You can pick anything you want and call it ground.



      This power supply box has two power supplies in it.
      Shorting the + of one to the - of the other puts the two power supplies in series. That gives you a so-called "split" power supply.



      You can call the middle connection ground and then you have +15V, 0V and -15V wires.



      Or you can call the right connection ground, and then you have +30V, +15V and 0V wires.



      Or you can call the left connection ground, and you get 0V, -15V and -30V wires.



      Note - some dual power supplies have the - of both supplies connected, inside the box. In that case, shorting the + of one to the - of the other would short out one of the supplies. This one doesn't have them connected.






      share|improve this answer














      You can pick anything you want and call it ground.



      This power supply box has two power supplies in it.
      Shorting the + of one to the - of the other puts the two power supplies in series. That gives you a so-called "split" power supply.



      You can call the middle connection ground and then you have +15V, 0V and -15V wires.



      Or you can call the right connection ground, and then you have +30V, +15V and 0V wires.



      Or you can call the left connection ground, and you get 0V, -15V and -30V wires.



      Note - some dual power supplies have the - of both supplies connected, inside the box. In that case, shorting the + of one to the - of the other would short out one of the supplies. This one doesn't have them connected.







      share|improve this answer














      share|improve this answer



      share|improve this answer








      edited Aug 30 at 11:11

























      answered Aug 29 at 5:34









      immibis

      1,193812




      1,193812







      • 4




        "Shorting the + of one to the - of the other puts the two power supplies in series" - but only if the two supplies are originally isolated from each other, and don't share a common negative rail.
        – Alnitak
        Aug 29 at 21:15












      • 4




        "Shorting the + of one to the - of the other puts the two power supplies in series" - but only if the two supplies are originally isolated from each other, and don't share a common negative rail.
        – Alnitak
        Aug 29 at 21:15







      4




      4




      "Shorting the + of one to the - of the other puts the two power supplies in series" - but only if the two supplies are originally isolated from each other, and don't share a common negative rail.
      – Alnitak
      Aug 29 at 21:15




      "Shorting the + of one to the - of the other puts the two power supplies in series" - but only if the two supplies are originally isolated from each other, and don't share a common negative rail.
      – Alnitak
      Aug 29 at 21:15












      up vote
      4
      down vote













      In most electronics, "Ground" is simply the point that we want to call "Zero Volts" - it need not have any relation to Earth (AC Power) Ground.



      That power supply appears to have three independent isolated supplies. The red line you show connects two of the supplies in series. If you consider that red line as "zero volts/circuit ground" you will have a positive supply from the left-most terminal, and a negative supply from the fifth terminal.






      share|improve this answer
























        up vote
        4
        down vote













        In most electronics, "Ground" is simply the point that we want to call "Zero Volts" - it need not have any relation to Earth (AC Power) Ground.



        That power supply appears to have three independent isolated supplies. The red line you show connects two of the supplies in series. If you consider that red line as "zero volts/circuit ground" you will have a positive supply from the left-most terminal, and a negative supply from the fifth terminal.






        share|improve this answer






















          up vote
          4
          down vote










          up vote
          4
          down vote









          In most electronics, "Ground" is simply the point that we want to call "Zero Volts" - it need not have any relation to Earth (AC Power) Ground.



          That power supply appears to have three independent isolated supplies. The red line you show connects two of the supplies in series. If you consider that red line as "zero volts/circuit ground" you will have a positive supply from the left-most terminal, and a negative supply from the fifth terminal.






          share|improve this answer












          In most electronics, "Ground" is simply the point that we want to call "Zero Volts" - it need not have any relation to Earth (AC Power) Ground.



          That power supply appears to have three independent isolated supplies. The red line you show connects two of the supplies in series. If you consider that red line as "zero volts/circuit ground" you will have a positive supply from the left-most terminal, and a negative supply from the fifth terminal.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Aug 29 at 6:25









          Peter Bennett

          34.3k12561




          34.3k12561




















              up vote
              4
              down vote













              It might be easier to understand if I would just draw a schematic of how
              this supply is configured:





              schematic





              simulate this circuit – Schematic created using CircuitLab



              So: only the port with the green marking and ground symbol is actually connected to earth (assuming you connected the supply properly to mains ground using the mains connector).



              If we ignore V3 (which you're not using in your example) then all outputs are "floating" sources, like batteries they can be used in almost any configuration you like. If you do not connect to earth but combine the supplies (for example to make 60 V by connecting V1 and V2 in series) then that combination is still floating relative to ground.



              In your example, the Earth/ground pin is unconnected so your supply is floating. V1 and V2 are in series but the potential relative to ground is still undefined.






              share|improve this answer






















              • Except, on the DP832, V2(-) and V3(-) are connected.
                – Jeroen3
                Aug 29 at 9:58










              • @Jeroen3 Indeed you're right, I missed that one, updating the schematic.
                – Bimpelrekkie
                Aug 29 at 9:59














              up vote
              4
              down vote













              It might be easier to understand if I would just draw a schematic of how
              this supply is configured:





              schematic





              simulate this circuit – Schematic created using CircuitLab



              So: only the port with the green marking and ground symbol is actually connected to earth (assuming you connected the supply properly to mains ground using the mains connector).



              If we ignore V3 (which you're not using in your example) then all outputs are "floating" sources, like batteries they can be used in almost any configuration you like. If you do not connect to earth but combine the supplies (for example to make 60 V by connecting V1 and V2 in series) then that combination is still floating relative to ground.



              In your example, the Earth/ground pin is unconnected so your supply is floating. V1 and V2 are in series but the potential relative to ground is still undefined.






              share|improve this answer






















              • Except, on the DP832, V2(-) and V3(-) are connected.
                – Jeroen3
                Aug 29 at 9:58










              • @Jeroen3 Indeed you're right, I missed that one, updating the schematic.
                – Bimpelrekkie
                Aug 29 at 9:59












              up vote
              4
              down vote










              up vote
              4
              down vote









              It might be easier to understand if I would just draw a schematic of how
              this supply is configured:





              schematic





              simulate this circuit – Schematic created using CircuitLab



              So: only the port with the green marking and ground symbol is actually connected to earth (assuming you connected the supply properly to mains ground using the mains connector).



              If we ignore V3 (which you're not using in your example) then all outputs are "floating" sources, like batteries they can be used in almost any configuration you like. If you do not connect to earth but combine the supplies (for example to make 60 V by connecting V1 and V2 in series) then that combination is still floating relative to ground.



              In your example, the Earth/ground pin is unconnected so your supply is floating. V1 and V2 are in series but the potential relative to ground is still undefined.






              share|improve this answer














              It might be easier to understand if I would just draw a schematic of how
              this supply is configured:





              schematic





              simulate this circuit – Schematic created using CircuitLab



              So: only the port with the green marking and ground symbol is actually connected to earth (assuming you connected the supply properly to mains ground using the mains connector).



              If we ignore V3 (which you're not using in your example) then all outputs are "floating" sources, like batteries they can be used in almost any configuration you like. If you do not connect to earth but combine the supplies (for example to make 60 V by connecting V1 and V2 in series) then that combination is still floating relative to ground.



              In your example, the Earth/ground pin is unconnected so your supply is floating. V1 and V2 are in series but the potential relative to ground is still undefined.







              share|improve this answer














              share|improve this answer



              share|improve this answer








              edited Aug 29 at 10:01

























              answered Aug 29 at 6:23









              Bimpelrekkie

              41.8k23790




              41.8k23790











              • Except, on the DP832, V2(-) and V3(-) are connected.
                – Jeroen3
                Aug 29 at 9:58










              • @Jeroen3 Indeed you're right, I missed that one, updating the schematic.
                – Bimpelrekkie
                Aug 29 at 9:59
















              • Except, on the DP832, V2(-) and V3(-) are connected.
                – Jeroen3
                Aug 29 at 9:58










              • @Jeroen3 Indeed you're right, I missed that one, updating the schematic.
                – Bimpelrekkie
                Aug 29 at 9:59















              Except, on the DP832, V2(-) and V3(-) are connected.
              – Jeroen3
              Aug 29 at 9:58




              Except, on the DP832, V2(-) and V3(-) are connected.
              – Jeroen3
              Aug 29 at 9:58












              @Jeroen3 Indeed you're right, I missed that one, updating the schematic.
              – Bimpelrekkie
              Aug 29 at 9:59




              @Jeroen3 Indeed you're right, I missed that one, updating the schematic.
              – Bimpelrekkie
              Aug 29 at 9:59










              up vote
              1
              down vote













              0V differential is called a virtual ground as in Op Amp inputs, even though without connections they are high input impedance.



              Any 0V reference can be called "ground" in electronics ( but not earth bonded ground).



              I believe you are referring to when a dual supply has a jumper from V1- to V2+ giving a floating virtual 0V ground reference in between and bipolar outputs.






              share|improve this answer
























                up vote
                1
                down vote













                0V differential is called a virtual ground as in Op Amp inputs, even though without connections they are high input impedance.



                Any 0V reference can be called "ground" in electronics ( but not earth bonded ground).



                I believe you are referring to when a dual supply has a jumper from V1- to V2+ giving a floating virtual 0V ground reference in between and bipolar outputs.






                share|improve this answer






















                  up vote
                  1
                  down vote










                  up vote
                  1
                  down vote









                  0V differential is called a virtual ground as in Op Amp inputs, even though without connections they are high input impedance.



                  Any 0V reference can be called "ground" in electronics ( but not earth bonded ground).



                  I believe you are referring to when a dual supply has a jumper from V1- to V2+ giving a floating virtual 0V ground reference in between and bipolar outputs.






                  share|improve this answer












                  0V differential is called a virtual ground as in Op Amp inputs, even though without connections they are high input impedance.



                  Any 0V reference can be called "ground" in electronics ( but not earth bonded ground).



                  I believe you are referring to when a dual supply has a jumper from V1- to V2+ giving a floating virtual 0V ground reference in between and bipolar outputs.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Aug 29 at 5:35









                  Tony EE rocketscientist

                  57.2k22082




                  57.2k22082



























                       

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