Voltage divider (circuit analysis)

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SUMMARY

The discussion focuses on using the voltage divider rule to solve for V1 in a circuit analysis involving a 10k ohm resistor. The user calculates V1 as V1 = (Vx - V1)(10/15) = -20V, but questions the correctness of this approach. The loop rule is applied to derive V_10k = 20V, leading to confusion regarding the calculation of V1 as 25V - V_10k = 5V. The conversation highlights the need for clarity in applying circuit analysis principles, particularly in determining voltage across resistors.

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  • Understanding of voltage divider rule
  • Familiarity with Ohm's Law
  • Knowledge of circuit loop analysis
  • Basic concepts of series and parallel resistors
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  • Learn about Kirchhoff's Voltage Law (KVL) for loop analysis
  • Explore resistor combinations in series and parallel
  • Investigate common circuit analysis tools like SPICE for simulation
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Electrical engineering students, circuit designers, and hobbyists interested in circuit analysis and voltage calculations.

Miike012
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How am I suppose to use voltage divider to solve for V1?

The first pic is the original pic
The second pic is me solving for V1,Vx, and V2

The third pic is and equivalent circuit of the first pic... I did this to reason that V1 is the voltage across the 10k ohm resistor.

Therefore using voltage divider...
V1 = (Vx - V1)(10/15) = -30(10/15) = -20V.

Is that the correct approach or is there an easier way?
 

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Presuming that the polarity shown on the 10k device is the polarity that appears across the diamond,
loop rule is 25V - V_10k - ½V_10k + ¼V_10k = 0 , so that V_10k = 20V = -Vx. (otherwise Vx=14.28V)
(but why isn't their V1 = 25V - V_10k = 25V - 20V = 5V?)
 
lightgrav said:
Presuming that the polarity shown on the 10k device is the polarity that appears across the diamond,
loop rule is 25V - V_10k - ½V_10k + ¼V_10k = 0 , so that V_10k = 20V = -Vx. (otherwise Vx=14.28V)
(but why isn't their V1 = 25V - V_10k = 25V - 20V = 5V?)

im confused as to how you came up with the equation 25V - V_10k - ½V_10k + ¼V_10k = 0 .

shouldnt it be...
Eq 1.
25 - Vx/4 + V5 + V10 = 0 ?
and
V10 = Vx.


Next...

V5 = I(5kohm) and I = Vx/(10k ohm).

Now from Eq 1.

25 - Vx/4 + Vx/2 + Vx = 25 + 5/4Vx = 0

and Vx = -25*4/5 = -20



(but why isn't their V1 = 25V - V_10k = 25V - 20V = 5V?)...

I added the third picture in my paint document that shows that V1 is the voltage across the 10 ohm resis.
 
Last edited:

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