Difference in capacitor configuration

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Discussion Overview

The discussion revolves around the performance differences in capacitor configurations, specifically focusing on how the arrangement of capacitors affects time and resistance in a circuit. Participants explore various configurations and their implications for circuit performance, particularly in the context of a project involving sizable doorknob capacitors.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant inquires about the performance differences based on capacitor lead connections and configurations.
  • Another suggests estimating or measuring the resistances of connections to determine network impedances and their impact on performance.
  • A participant explains the rules for adding resistance and capacitance in parallel and series configurations, proposing that increasing capacitance decreases resistance and vice versa.
  • One participant asks for more details if the frequency is in the MHz range and shares a technique for connecting capacitors using short, large conductors for lower frequencies.
  • A later reply provides additional context about the specific capacitors being used (1400pF doorknob capacitors) and the connection method (braided 8 gauge wire), indicating a frequency likely in the couple hundred kHz range.

Areas of Agreement / Disagreement

Participants express varying levels of detail and approaches to the problem, with no consensus on the best configuration or its impact on performance. Multiple viewpoints on the significance of connection methods and frequency effects remain present.

Contextual Notes

Participants have not provided specific calculations or measurements, and there are unresolved assumptions regarding the frequency range and the exact configuration details that may influence performance.

IHateMayonnaise
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Hello!

I am working on a project at the moment and I have the option of connecting my capacitors in a number of different ways. My question deals with the possible difference in time, resistance to my circuit depending on where I connect the leads. What I really want to know is if there will be a significant difference in performance between each of the configurations.

For simplicity, I have attached an illustration made in Paint (forgive me please). The capacitors are connected in parallel.

The configurations are listed from easiest, to the least-easiest. Of course there is not much of a difference from the easiest to the least-easiest, however I do believe that this is good information to know.

Thanks!
 

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I think the best way to find out is to estimate or measure the resistances of the connections, and work out the different network impedances yourself. Depending upon the application, you will then see whether it makes a difference or not.
 
Remember that resistance in parallel adds reciprocally, whereas capacitance in parallel adds directly; resistance in series adds directly, whereas capacitance in series adds reciprocally. So as an overall rule for your network, where you increase capacitance you decrease resistance, and vice versa. You may want to work toward an optimum product of capacitance times resistance, or generalized RC time constant for the circuit.
 
Are you in the MHz range? If so, you must provide much more detail.

For lower frequencies and large caps, the technique I've always used is to strap the caps together with very large, very short, conductors. I've even used stranded braid. If you do that, the question is moot.

If these are small caps on a board, simply minimize lead length.
 
Thank you vanesch and Loren Booda for your replies!

TVP45 said:
Are you in the MHz range? If so, you must provide much more detail.

I have not calculated the exact value yet, however it will likely be on the order of a couple hundred Khz. They are pretty sizable doorknob capacitors, at 1400pF. To connect them I am using braided 8 gauge wire (aka, car battery jump cable). I can list off much more precise details as needed. Thanks!
 

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