Please help Circuit analysis (Thevenin voltage and internal resistance)

AI Thread Summary
The discussion focuses on two main questions regarding circuit analysis related to Thevenin voltage and internal resistance. The first question involves proving that the internal resistance of the meter movement (RI) equals (RS)(RP)/(RS-RP), with the user struggling to apply circuit reduction techniques. The second question seeks to determine the Thevenin voltage (VTH) for a circuit, with an open circuit voltage measured at 0.790V and a calculated Thevenin resistance of 1,500 Ohms. Suggestions for finding VTH include calculating the short circuit current at the load terminals and applying the appropriate circuit analysis methods. The urgency of the lab deadline adds pressure to resolve these circuit analysis challenges.
Odyssey
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URGENT! Please help! Circuit analysis (Thevenin voltage and internal resistance)

Hi guys,
I am really stuck on this portion of my lab and it's due tomorrow! Please help!

I have two questions:
The first deals with the diagram from the left of the attached picture. I have to prove that RI (internal resistance of the meter movement) is equal to (RS)(RP)/(RS-RP). I tried reducing the circuit through circuit analysis (Rs = R1+R2+... and 1/Rp=(1/R1)+(1/R2)+...) but it doesn't work. Please give me some pointers, thank you.

The second question is about the circuit on the right. I have to find the Thevenin voltage for this circuit. I know this is equal to the open circuit voltage which I measured to be 0.790V in the lab. I found the Thevenin resistance to be RTH=1,500 Ohms by circuit analysis. Please give me some ideas on how to solve for VTH, thank you!
 

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Don't know what the circuit looks like, but the procedure for finding the look in resistance is to turn off all your sources. Open circuit your current sources and short circuit your voltage sources.

You can solve for the Thevenin voltage by finding the short circuit current at the load terminals.
 

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