There is something really confusing me. If I have acquired an equation from my circuit (electronic circuit) of KVL like ID=VSS-RS*IS then can I assume, for example, that the value of ID isn't related to value of RD? If so why?

I know in the equation of ID there's no value of RD, but who said that it's not related? Maybe it is related and does not appear on the equation! Who knows?

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    \$\begingroup\$ Tony, I've tidied up your post fixing punctuation, capitalisation, etc. Don't add spaces before punctuation as it messes up line breaks, etc. (as well as being wrong). See Write to the best of your ability on the site's help pages. \$\endgroup\$
    – Transistor
    Jun 22 '19 at 8:44
  • \$\begingroup\$ What is Id? And if Id is the current, how can current be equal to the differences of voltages? \$\endgroup\$
    – G-aura-V
    Jun 22 '19 at 8:58
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    \$\begingroup\$ I suggest you start with showing use the circuit and how you derived that formula. \$\endgroup\$
    – Oldfart
    Jun 22 '19 at 9:27
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    \$\begingroup\$ I'm voting to close this question as unclear, because there's no way of explaining a wrong equation. Tony, I'm sorry. You're asking a wild mix of questions that all (every single one) point to you needing to go back, and read a good book on the very basics of linear circuit theory, from the beginning. You seem to be burdened with some false notions, and you fire questions that make no sense at us at a rate that really suggests you're grasping for straws of knowledge to hold on to. So, please, try getting a good book, forgetting everything you know so far, and begin from the start. \$\endgroup\$ Jun 22 '19 at 15:43

First, your equation is not a valid KVL equation. You have a current on the left side and two voltage terms on the right side. I'll assume that you just made up this equation, and that a real equation would consist only of voltage terms.

Unless you have a trivial circuit with just one loop, you can't look at a single KVL equation and say that unknown value X does not depend on known parameter Y. You need to create the entire system of equations, which means you need as many independent equations as you have unknown quantities. If parameter Y does not appear in any of these equations then you might be able to conclude that parameter Y has no effect on the unknown values.


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