Voltage Divider - Understanding Two Circuits

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Discussion Overview

The discussion revolves around understanding the behavior of voltage divider circuits with different voltage references, specifically comparing a circuit with a +5V and ground to one with +5V and -5V. Participants explore the implications of these configurations on voltage measurements and potential differences.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the output voltage of a voltage divider with +5V and ground, suggesting it would be 2.5V.
  • Another participant proposes that for a voltage divider with +5V and -5V, the output would be 0V, calculated as (5V - (-5V))/2.
  • Concerns are raised about the terminology of ground and its relationship to the -5V terminal, questioning if they are at the same potential.
  • A participant notes that the interpretation of ground may depend on whether a single rail or split supply is used, providing examples of how different configurations can affect potential definitions.
  • Another participant emphasizes that the definition of voltages in relation to ground requires an understanding of where 'zero volts' is established in the power supply setup.

Areas of Agreement / Disagreement

Participants express confusion and differing interpretations regarding the relationship between ground and the negative voltage terminal, indicating that multiple competing views remain without a consensus.

Contextual Notes

Participants mention various configurations of power supplies, including single rail and split supply systems, which may affect how voltages are referenced and understood. There is also ambiguity regarding the definition of ground in different contexts.

Who May Find This Useful

This discussion may be useful for individuals interested in electronics, particularly those seeking to understand voltage references in circuit design and the implications of different power supply configurations.

autopsygreen
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Very silly doubt...If say I had a voltage divider circuit with 2 equal Resistance say R applied between
1.V=5v and ground
2.V=5V and V=-5V
Whats the answers and what the difference?
I guess the answer for the 1 Q will be (5/2)...
Please explain the second ...Thank you
 
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(5v - -5v)/2

0v
 
What confuses me is then why is the negative terminal said to be connected to ground.
Shouldnt that mean the ground and -5v are at same potential
 
autopsygreen said:
What confuses me is then why is the negative terminal said to be connected to ground.
Shouldnt that mean the ground and -5v are at same potential

depends on if its a single rail supply...

+5V and GND (0V or negative line of power supply)

or a split supply where you have say...

+5V, 0V, -5V where the 0V rail may be connectd to GND via the PSU case and mains earth


take a 12V battery, you have a + and - terminal --- from a circuit point of view the - terminal can be called 0V

now take a mains sourced 12V power supply, you have a +12V rail and a -(neg) 0V rail.
that negative rail may be floating ie. not connected to the case of the equip. Or it may be connected to the case and that case is also connected to GND via the Earth lead of the mains cable.

just a few random thoughts ;)

Dave
 
By stipulating a +5 and -5V supply, you are implying that there is a 'zero volts' somewhere in the power supplies, connected to ground which defines their voltages wrt ground.
 

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