Hi. I'm having trouble on this problem, and hopefully someone here can help me. It seems really simple, but every way I try to do it either leads to a dead end, or in one case, a very complicated answer that's probably wrong.(adsbygoogle = window.adsbygoogle || []).push({});

Here's the problem (the picture's attatched). R_{S}is the internal resistance of the battery, and is 35 Ohms when it's new and gets up to 200 after it wears down. R1 and R2 must be chosen to fit the following specifications: 1) V_{out}must be between 4 and 5 volts when no load is attatched. 2) V_{out}cannot go down by more than 5% when a load R_{L}is attatched. The answers may or may not involve R_{L}.

After trying a few things that went nowhere, I finally found a way that seemed to work. I was able to find the region in the R1-R2 plane where the V_{out}will be between 4 and 5 (a wedge with the corner at about (258,367) and slopes 4/5 and 5/4). So any (R1,R2) in this region that satisfies the 5% requirement would be an answer. The problem is that the region which satisfied the 5% inequality was underneath a hyperbola, and it didn't always intersect the other region, depending on R_{L}(after doing a lot of work, I'm pretty sure R_{L}must be greater than R1, which can't be less than 258). Not only did the problem not give any restrictions on R_{L}, but it was much more work than I thought it would be. Both of these lead me to believe I'm wrong and/or doing it a much harder way than necessary. Thanks in advance.

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# Homework Help: Circuit design problem

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