Can I find a general solution to this circuit?

AI Thread Summary
The discussion centers on finding the equivalent resistance of a circuit with varying numbers of R3 resistors. It is suggested that there may not be a general solution due to the complexity of the calculations involved. However, one participant proposes analyzing the circuit by removing certain resistors to simplify the problem. They establish a relationship between the resistance functions R(n) and R(n+1), leading to an approximation for large n. Ultimately, this approach allows for easier calculations similar to those used in infinite ladder circuits.
Lotto
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TL;DR Summary: I have to find an equivalent resistance of the circuit below, dependent on the amount of ##R_3## - resistors.

Here is the circuit:
circuit2.jpg

I think there is no general solution. When I want to calculate it, I have to do ##((((R_1+2R_2)^{-1}+{R_3}^{-1})^{-1}+2R_2)^{-1}+{R_3}^{-1})^{-1}...##, so it is kind of crazy. Is there any general solution dependent on the amount of ##R_3## - resistors ##n##? So something like ##R_{\mathrm {eq} _n}=....##.
 
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Google "ladder circuit". You will find methods for dealing with problems like this.
 
Lotto said:
TL;DR Summary: I have to find an equivalent resistance of the circuit below, dependent on the amount of ##R_3## - resistors.

Here is the circuit:
View attachment 326155
I think there is no general solution. When I want to calculate it, I have to do ##((((R_1+2R_2)^{-1}+{R_3}^{-1})^{-1}+2R_2)^{-1}+{R_3}^{-1})^{-1}...##, so it is kind of crazy. Is there any general solution dependent on the amount of ##R_3## - resistors ##n##? So something like ##R_{\mathrm {eq} _n}=....##.
My first step would be to leave out the two R1s. Those can be put back in later.
The resistance of the remaining system is a function R(n). Can you figure out the relationship between R(n) and R(n+1)?
 
haruspex said:
My first step would be to leave out the two R1s. Those can be put back in later.
The resistance of the remaining system is a function R(n). Can you figure out the relationship between R(n) and R(n+1)?
Yes, I did it and I made an approximation when ##n## is big, so we can say that ##R_n \approx R_{n-1}##, similary as when we solve an infinite ladder circuit. Then it was easy to solve.
 
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