Understanding resistors and voltage drop

In summary, the homework statement is trying to determine the resistor, the missing I's and V's. The Attempt at a Solution states that the equation for resistors is R1+R2+R3+R4, and that the unknowns are V1, V2, V4, Vs, Req, and R3. R3 is 10 Ohms and Req is 70.01 k Ohms. V1 is 6000V, V2 is 8800V, V4 is 13200V, and Vs is 28004V.
  • #1
talaroue
303
0

Homework Statement


Determine Req, the missing I's and V's?

Interpertation.jpg





Homework Equations


V=IR



The Attempt at a Solution



First problem is that I thought I learned that R2 and R3 are in parallel so you have to use the recipercal rule, but looking back at my notes for Interpetation for C.E. I saw that he said that all of these are in series, as you can see this dellima will mess up my Req. So my question is, do I find Req for R2 and R3 then add those to R1 and R4 to get Req, or is it simple R1+R2+R3+R4. And why?

But besides that I need to find R3 which i thought I could use V3=iR
i is given as 400mA, so R3 is 10 Ohms. This doesn't look right seeing as all the other resistors are in the thousands(1kOhm=1000Ohms).

Am i on the right track?
 
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  • #2
R1, R2, R3, R4 are all in series because there any electron going from one terminal of the battery to the other must pass through all four. So resistance adds: Req=R1+R2+R3+R4.

Your calculation for R3 seems right. I've no idea why it's not of a similar order of magnitude as the other resistances.
 
  • #3
Thanks for that, now what about for the Req?
 
  • #4
As the last poster said:
Req=R1+R2+R3+R4.

Just add up all the resistances.

You can get the supply voltage by using I*Req. It is VERY high. You can get all the voltages across the resistors the same way. They should add up to the supply voltage.

{But please post clearer photos (all digital cameras have a closeup setting on them) and please don't use abbreviations and acronyms without explaining them.}
 
  • #5
That was taken by phone, I don't have a digital camera with me. It was hard to get a good picture because it was very small on the paper, so the closer i got or zoomed in the blurry it got I tried me best.
The reason I abbreviated them was because the were already abbreviated in the photo.

Thanks for your help. It just seemed weird because the R3 was really small compared to everywhere else!
 
  • #6
Here is what I believe it is right...

The unknowns are V1,V2,V4,Vs, Req,R3.

R3=V3/it=4V/400mA=10 Ohms

Req=15kOhm+22kOhm+10Ohms+33kOhms=70.01 k Ohms

V1=it*R1=6000V

I repeated the step to solve for V1 for V2V4.

Vs=6000V+8800V+13200V+4V=28004V

What do you think?
 
  • #7
Looks good.Did you know that if you hold a magnifying glass in front of your camera lens, it will act as a close-up lens and let you focus closer?
Focus the sun onto something and measure the distance from the lens to the focussed sun and that is the focal length of the lens.
Now, put the lens in front of your phone camera and whatever you want to photograph at the distance you measured and it should be in focus. Get good lighting on it (outside, but not in the sun) and you will start to get good photos. Not as good as a real camera, but better anyway.
 
Last edited:
  • #8
Thanks for the advice I am sure I will use it when I soon! I am sure ill be posting on here a lot more haha.
 

1. What is the purpose of a resistor?

A resistor is an electronic component that is used to limit the flow of electric current in a circuit. It is typically used to control the amount of voltage or current within a circuit, and is essential in regulating the power and preventing damage to other components.

2. How is voltage drop related to resistors?

When current flows through a resistor, there is a decrease in voltage across the resistor. This is known as voltage drop and is caused by the resistance of the material the resistor is made of. The amount of voltage drop is directly proportional to the amount of current flowing through the resistor.

3. What factors affect the resistance of a resistor?

The resistance of a resistor is affected by its material, length, and cross-sectional area. Different materials have different levels of resistance, with some being more conductive than others. The longer the resistor, the more resistance it will have. Similarly, a resistor with a smaller cross-sectional area will have more resistance than a resistor with a larger cross-sectional area.

4. What is the difference between a fixed and variable resistor?

A fixed resistor has a set resistance value that does not change. It is used in circuits where a specific amount of resistance is needed. On the other hand, a variable resistor, also known as a potentiometer, has a variable resistance that can be adjusted manually. This is useful in circuits where the resistance needs to be changed, such as in volume controls for speakers.

5. How can I calculate the voltage drop across a resistor?

The voltage drop across a resistor can be calculated using Ohm's law, which states that voltage (V) equals current (I) multiplied by resistance (R). So, V = I x R. You can also use Kirchoff's voltage law, which states that the sum of the voltages in a closed loop circuit must be equal to zero.

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