Comparing Two Circuits: Can We Say Low Pass Filter?

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Discussion Overview

The discussion revolves around the characterization of two circuits, one stimulated by a current source and the other by a voltage source, and whether the first can be classified as a low pass filter. Participants explore concepts related to source transformation and the implications for cascading filters.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions if the circuit stimulated by a current source can be classified as a low pass filter, given that both circuits yield the same output voltage.
  • Another participant mentions source transformation, explaining that a voltage source with a series resistor can be transformed into a current source in parallel with the same resistance.
  • A different participant expresses uncertainty about the practical application of source transformation and its relevance in cascading filters, noting the simplicity of RC circuits.
  • One participant suggests that to cascade filters, the next filter could be placed in parallel with the resistor and capacitor, allowing for the addition of currents and combining resistors in parallel.

Areas of Agreement / Disagreement

Participants express differing views on the utility of source transformation and the feasibility of cascading filters, indicating that the discussion remains unresolved regarding the classification of the circuit as a low pass filter and the method of cascading.

Contextual Notes

Some assumptions about the nature of the circuits and the conditions under which they operate are not fully explored, and there is a lack of consensus on the practical implications of source transformation.

somasimple
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Hi all,

Here is a picture of two circuits.
The one at the left is stimulated with a current source and the other with a voltage source.
They give the same results V(1) = V(2).
Is it possible to say that the primer is a low pass filter?
 

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Yes. Somewhere buried away in your textbook is something call source transformation. If you have a voltage source with a series resistor, you can transform it to a current source in parallel with the same resistance. The current source is simply the original voltage source divided by the resistor.
 
Thanks Corneo,

I wasn't aware of such circuit but find a good description in this http://books.google.com/books?id=sx...r=&ei=v5_AScGeEp-8zgTIwOH3Bw&hl=fr#PPA118,M1"
What is its interest by the way?
Normally the simple nature of RC cells give us an entry point and an exit one. This permits a cascading with two or more filters.
In this configuration the applied source is modified by the filter but I see no way to assemble multiple filters?
 
Last edited by a moderator:
What good is source transformation? Honestly I don't know. I have never ever had to use it at in career so far (2 years). If you want to cascade the filter, you could just place the next filter in parallel to the resistor and cap, the currents sources would add. The resistors would combine in parallel; the caps would add in value.
 

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