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Homework Statement
http://img509.imageshack.us/img509/5658/circuituz5.jpg
Find the current through resistor X for V = 7V
Homework Equations
Thevenin equivalence?
The Attempt at a Solution
Right I was advised a way to do this by assuming a 1A current flows through the resistor and then working back and scaling accordingly, but I also want to try this using Thevenin Equivalence. So I've worked out:
Vth = 0.46V and Rth = 4.28 ohms
Working for Rth:
Rth is the resistance seen across X with V shortcircuited. Thus, starting from right with 1 ohms (i.e. X) going to left
= [(((((((1||2) || 3) -- 2) || 7) -- 2 -- 1) || 4 -- 2) || 5) -- 2] , where || denotes parallel, -- denotes series. I think this is where I've messed up, giving me 4.28 ohms
Working for Vth:
Jus use voltage division from 7V all the way down to give 0.46V across X
So the Thevenin equivalent is:
0.46V in series with 4.28 ohms and then the load (resistor X) connected is 1 ohm in series.
This doesn't give the correct answer though. The current is supposed to be 0.125A.
Any feedback/help/advice very much appreciated!
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