Finding the values of resistors

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In summary, the conversation discusses the use of voltage divider and KVL to determine the values of resistors in a circuit. The equations used include Vi= [Ri / (R1+R2+...+Rn)] * Vs, 1/Rtotal = 1/R1 + 1/R2 + ... + 1/Rn, and Ʃrise + Ʃdrop = 0. The attempt at a solution involves finding the voltage for Req using KVL and then using the voltage divider equation to solve for the unknown resistor. The final solution involves using Ohm's Law to determine the value of R2 and solving the rest of the problem.
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ZeeAngel
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Homework Statement


In the problem i have to find the values of resistors using voltage divider, and use KVL to determine the currents.


Homework Equations



Vi= [Ri / (R1+R2+...+Rn)] * Vs

1/Rtotal = 1/R1 + 1/R2 + ... + 1/Rn

Ʃrise + Ʃdrop = 0

The Attempt at a Solution



In order for us to use voltage divider the resistors must be in series.

Req = (40*R2)/(40+R2), but we still don't know the resistance of R2.

However, later I tried to use the KVL equation to find the voltage for Req.

-24+8+Veq = 0 → Veq = 16 V

Then I used the voltage divider equation:

Veq = [Req / (R1 + Req) ]* Vs // but again we have two unknowns here again

And that's the point where I stuck, I know this problem is trivial but my brain cannot come up with anything else to solve this.
 

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  • #2
Using KVL, we know that Veq=24V-8V=16V. Using Ohm's Law, we can easily get R2=16V/1.6A=10 Ohms. The rest is obvious! :)
 
  • #3
Thank you very much :D
 

Related to Finding the values of resistors

1. What is the purpose of finding the values of resistors?

The purpose of finding the values of resistors is to determine their resistance, which is a measure of how much the resistor opposes the flow of electric current. This is important in designing and troubleshooting electronic circuits, as it helps to ensure the correct flow of current and prevents damage to components.

2. How do you calculate the value of a resistor?

The value of a resistor can be calculated using Ohm's Law, which states that resistance (R) is equal to the voltage (V) divided by the current (I). This can be represented by the formula R = V/I. Additionally, the color-coded bands on the resistor can be used to determine the resistance value according to a standardized color code chart.

3. What factors can affect the accuracy of finding the values of resistors?

The accuracy of finding the values of resistors can be affected by a few factors, such as the temperature of the resistor (as resistance can change with temperature), the precision of the measuring equipment, and the tolerance of the resistor. Variations in manufacturing can also affect the actual resistance value of a resistor.

4. Why is it important to use the correct units when measuring resistor values?

Using the correct units when measuring resistor values is important because resistance is measured in ohms (Ω), which is a unit of electrical resistance. Using the wrong units can lead to incorrect calculations and potentially damage the circuit or components.

5. Are there any alternative methods for finding the values of resistors?

Yes, in addition to using Ohm's Law and the color-coded bands, there are also other methods for finding the values of resistors. One method is to use a multimeter, which can directly measure the resistance of a resistor. Another method is to use a Wheatstone bridge, which is a circuit specifically designed for measuring resistance accurately.

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