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Anyone know electrical physics?
- Thread starter rye9
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It's been a while since I took a circuits class, but a simple google search lead me to this result: http://www.calvin.edu/~svleest/circuitExamples/equRes/
the 6th example should help you out. the site has hints, solution to examples and pspice sims.
the 6th example should help you out. the site has hints, solution to examples and pspice sims.
I think you are going to have to write a bunch of equations then play around with them solve for the unknowns.
Define a bunch of currents: i1 is the current through R1, i2 is the current through i2, and so on.
The current out of the battery has to equal the current returning to the battery. So i1+i2 = i4+i5.
Because of the way the 1 ohm resistors are placed (R1 and R5) some of the current through R1 will go through R3 and the rest through R4. So we write two more equations: i1 = i3+i4 and i5 = i2+i3.
You also need to write equations for the R1-4 node and the R2-5 node: V14 = 14-(1*i1) and V14 = 2*i4 and V25 = 14-(2*i2) and V25 = 1*i5.
Lastly (maybe) we know that V14 = V25+ i3*1. All that is left is a bunch of substitutions and rearranging until the answer pops out. Easy
but I'm too lazy to do it.
It's easy to find the min and max that it could be. If R3 was missing (open) then there would be two 3 ohm loads on the battery. So 14/1.5 = 9.333 Amps. If R3 was shorted then R1 and R2 would parallel to 0.667 ohms and so would R4 and R4. So the load on the battery would be 1.333 ohms giving a current 10.5 ohms.
Since R3 is between 0 and infinity ohms the battery current must be between 10.5 and 9.333 Amps.
Good luck - Greg
Define a bunch of currents: i1 is the current through R1, i2 is the current through i2, and so on.
The current out of the battery has to equal the current returning to the battery. So i1+i2 = i4+i5.
Because of the way the 1 ohm resistors are placed (R1 and R5) some of the current through R1 will go through R3 and the rest through R4. So we write two more equations: i1 = i3+i4 and i5 = i2+i3.
You also need to write equations for the R1-4 node and the R2-5 node: V14 = 14-(1*i1) and V14 = 2*i4 and V25 = 14-(2*i2) and V25 = 1*i5.
Lastly (maybe) we know that V14 = V25+ i3*1. All that is left is a bunch of substitutions and rearranging until the answer pops out. Easy
but I'm too lazy to do it.It's easy to find the min and max that it could be. If R3 was missing (open) then there would be two 3 ohm loads on the battery. So 14/1.5 = 9.333 Amps. If R3 was shorted then R1 and R2 would parallel to 0.667 ohms and so would R4 and R4. So the load on the battery would be 1.333 ohms giving a current 10.5 ohms.
Since R3 is between 0 and infinity ohms the battery current must be between 10.5 and 9.333 Amps.
Good luck - Greg
