Design a Circuit: Solve Homework Statement

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The discussion revolves around designing a circuit using two ideal batteries (1.5 V and 9.0 V) and three 120 Ω resistors to achieve a current of 21 ± 1 mA. Initial attempts included various combinations of resistors and batteries, with one approach yielding a current of 25 mA when all resistors were in series with the 9.0 V battery. The solution was ultimately found by placing the resistors in series and opposing the EMFs, resulting in the desired current of 21 mA. The participant expressed skepticism about the practical utility of such circuit design problems. The thread concludes with the successful resolution of the homework statement.
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Homework Statement



You are given two ideal batteries with ##\epsilon_1 = 1.5 V## and ##\epsilon_2 = 9.0 V##. You are also given three ##120 \Omega## resistors.You may use any or all of the components. Design a circuit where there is a current of ##21 \pm 1 mA## through at least one of the resistors.

Do NOT use EMF sources in parallel.

Homework Equations


The Attempt at a Solution



I've already tried several combinations of resistors and batteries with no avail. The closest I've been is when all three resistors are in series with the ##9.0 V## emf. Then the current across the whole circuit is ##25 mA##. I've also tried creating several multiloop circuits, but those haven't worked either.

Anyone have some design advice? It would be very appreciated.

EDIT: Never mind guys I got it, just place the resistors in series and then oppose the emfs. Then the current is ##\frac{9.0-1.5}{360} = 21 mA##.
 
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glad to see you got it. I've never understood the utility of such problems, they just seem silly to me but I've seen them before.
 
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