IC power-supply pin - Wikipedia
en.wikipedia.org

I am reading up on logic circuits, families and levels because it’s fun. I have no formal education in physics, computing or electronics.

For power supplies, sometimes one of the supply rails is referred to as ground (abbreviated “GND”) – positive and negative voltages are relative to the ground. In digital electronics, negative voltages are seldom present, and the ground nearly always is the lowest voltage level. In analog electronics (e.g. an audio power amplifier) the ground can be a voltage level between the most positive and most negative voltage level.

I know from previous reading, that electricity - at least when it comes to direct current, but perhaps even when it comes to AC? - has a way in (“line”?) and a way out (“neutral” or “ground”? - disregarding for a second the fact that ground also carries current in case of a ground fault).

Again, from previous reading, I know that we work computers by either supplying them voltage or not (or in some circuits a higher voltage and a lower voltage). In any case, it’s a choice between one or the other, since that is what we are trying to represent: boolean true or false.

So, what is this “negative voltage”? Is this a figure of speech or can voltage actually have a negative value? The part from the article that I quoted above states in relativistic terms, that “the ground can be a voltage level between the most positive and most negative voltage level” (italic text by me), which makes me assume “yes”. But if voltage is electromotive force, how can it be negative? I amusingly imagine a force “sucking” the current backwards. 🤭

Explain it to me as if I was five. 👶

  • nous@programming.devEnglish
    2·
    20 hours ago

    Nothing to do with the electrical grid. It is just that the positive lead of the output of the power supply is whatever voltage you select above the negative lead on the output side of the power supply. Those are the two relative points in this situation. You can call the negative lead ground if you want. Wiring diagrams for the device you connect it to will likely call it ground. It is not the same thing as the grounding wire in a plug socket.

    Note that the grounding wires in a home have nothing to do with any live circuit in your house. They are to make faults in the system safer by giving a path for electrons to flow if a conductive casing ever gets into contact with a live wire. In normal operation nothing should be flowing through it at all. With doubly insulated devices (like that power supply) the grounding wire in the plug socket is probably not connected to anything at all in the device. The plug likely does not even have a grounding wire in it.

    • printf("%s", name);@piefed.blahaj.zoneOPEnglish
      1·
      18 hours ago

      Thanks for the clarification! So, there is an overlap, then, when it comes to the term “ground”? Grounding - and its wiring - in the greater electric grid is actually there in case there is a ground fault, while ground wires in smaller DC circuits can refer to the “outgoing” lead/terminal/wire?