How are Resistance, Capacitance and Time related?

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Discussion Overview

The discussion revolves around the relationship between resistance, capacitance, and time, specifically focusing on the time constant in RC circuits. Participants explore theoretical aspects and mathematical expressions related to these concepts without revealing foundational information such as current, voltage, or charge.

Discussion Character

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

Main Points Raised

  • Some participants express difficulty in discussing the topic without referencing basic electrical concepts like current, voltage, or charge.
  • One participant clarifies that they were referring to the time constant, denoted as τ, which is defined by the equation τ = RC.
  • Another participant elaborates on the time constant, stating that five times the time constant is considered the "steady state" where a capacitor no longer charges significantly.
  • A mathematical expression for the voltage across a capacitor over time is presented: Vc(t) = Vf(1 - (e^-t/[tau])), where Vf is the total voltage and [tau] is the time constant.
  • It is mentioned that in an RC circuit, as the voltage across the capacitor increases, the voltage across the resistor decreases, highlighting the interplay between these components.
  • One participant notes that while the time constant is applicable to capacitors and other fields of electrical engineering, it does not fully describe the entire relationship between resistance, capacitance, and time.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and interpretation of the time constant and its implications in RC circuits. There is no consensus on the completeness of the relationship between resistance, capacitance, and time, as some participants suggest limitations in the discussion.

Contextual Notes

Some assumptions about foundational electrical concepts are not explicitly stated, which may affect the clarity of the discussion. The mathematical steps and definitions related to the time constant and its application in different contexts remain unresolved.

Sociopath^e
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without revealing any sort of base info such as current, voltage or charge
 
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Originally posted by Sociopath^e
without revealing any sort of base info such as current, voltage or charge

That's like asking to drink something that isn't a liquid.
 
well it doesn't matter, i found out in the end, i meant time *constant*
so its τ = RC
 
well since I am new here and I feel like a peon compared to some of the genius minds here, I'll explain some more about resistance, capacitance, and time because its something I actually understand!

[tau] = RC you knew that.. but 5 * the time constant of the circuit is considered the "steady state" in which a capacitor doesn't charge anymore.

As time increases, the capacitance increases exponentially according to a certain equation: Vc(t) = Vf( 1 - (e^-t/[tau]) ) where Vf is the total voltage, t is the time in which you would like to observe the voltage "on" the capacitor, and [tau] is the time constant.

since an RC circuit is (when reduced according to Thevenin for all of you critics, hehe ) a series circuit, the voltage across the resistor will be the total votage minus the voltage across the capacitor at that time, so as the voltage across the capacitor rises, the voltage across the resistor falls.

Probably more than you wanted to know, but hey I figured I might as well make a good impression, because I'll probably be sounding like a jackass rather soon.
 
time constant is appliable to condensators and other fields of el. engineering, but it doesn't reveal whole RCT function.
 

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