Does current flow from point A to ground in electrical circuits?

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Discussion Overview

The discussion revolves around whether current flows from a specific point in an electrical circuit to ground, exploring the concept of ground as a reference point with zero electrical potential. Participants examine the practical implications of grounding in circuit design and its relevance to calculations and real-world applications.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that there is no current flowing to ground for the components shown in the circuit diagram.
  • Others suggest that while there may be no direct current to ground, external factors such as signal interference can affect circuit performance, and grounding can help mitigate these effects.
  • One participant questions the interpretation of the circuit diagram, suggesting that a DC current could be flowing through a resistor, indicating a potential misunderstanding among participants.
  • It is noted that in practical applications, the ground node is often not necessary for the circuit's operation, but is required for simulation software like SPICE to perform calculations.
  • A participant discusses the concept of ground as an approximation, highlighting that real conductors have resistance and inductance, which can lead to voltage drops when current flows.
  • Different categories of grounds are proposed, including signal return, analog ground, digital ground, power ground, chassis ground, and safety ground, each serving specific purposes in circuit design.

Areas of Agreement / Disagreement

Participants express differing views on the necessity and function of ground in the circuit, with some asserting no current flows to ground while others highlight the complexities and practical considerations of grounding. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants acknowledge limitations in their descriptions of grounding categories and the complexities involved in interconnecting grounds, as well as the potential for noise and offset issues in circuit design.

ch3cooh
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Is there any current flows from point A to the ground (see the attachment)?

We use ground node to idicate somewhere in the circuit has ZERO electrical potential. Do we really connect that point to the ground in real world or we just mark that point to make it easier to do calculations?
 

Attachments

  • ground node.PNG
    ground node.PNG
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Your second post...Ethanoic.

There is no current to ground for the components shown. In practice, there can be signal sources that are not shown, they are incidental and usually unwelcome. Example: 50Hz hum induced in that wiring due to proximity to mains wiring, or radio frequencies inducted by nearly or distant stations, or passing taxis with 2-way radios, or motors or car ignitions, or computer chip signals, etc., etc. The Earth connection can divert these and render them inconsequential to the operation of your circuit.

The Earth connection may be shared by other circuits, not shown here, but possibly partnering it in some way. It represents a piece of wire, not a connection to terra firma, usually. :smile: Often it's a connection to an area of copper on a circuit board.
 
NascentOxygen said:
There is no current to ground for the components shown.

Are we looking at the same diagram? It looks like a DC current of Vbattey/R would be flowing through the resistor. What am I missing?
 
In the real world and for this circuit this point - GND - is not needed. SPICE requires a GND node - that is where it starts all of it's calculations from.
 
The idea of having a surface or conductor with 0 volts (ground) at all points is a useful concept, but in reality, it's best an approximation.
All practical conductors suffer from resistance and inductance. Thus if current flows between any two points on a conductor, there will be a corresponding voltage drop.
For this reason, circuit designers separate grounds into different categories:
* Signal return - For remote instruments or microphones
* Analog ground - For low current small signal regions
* Digital ground - Used for micro-controllers and digital circuitry (which tend to have high frequency currents)
* Power ground - Used to carry high di/dt currents within the power supply regions
* Chassis ground - Used for safety and as a place to tie down high frequency currents.
* Safety ground (or neutral) - Used with chassis ground as a means of routing dangerous currents away from users.

I may not have been complete or given the best description on some of these, but they are the common ones I think about. There's also a slew of work on how you interconnect grounds, and how you deal with noise / offset related issues...
 

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