How Do You Calculate R1 and R2 for Temperature-Independent Resistance?

AI Thread Summary
To achieve a constant resistance of 30 ohms independent of temperature, a combination of an aluminum resistor (R1) and a carbon resistor (R2) is required. The temperature coefficients of resistance are crucial, with aluminum having a positive coefficient (α1 = 3.9 x 10^-3) and carbon a negative coefficient (α2 = -0.5 x 10^-3). The total resistance in series can be expressed as R_total = R1 + R2, and the change in resistance with temperature must be balanced to maintain the desired constant value. Calculating R1 and R2 involves setting up equations based on their respective temperature coefficients and solving for the resistances at 0 degrees Celsius. This approach ensures the overall resistance remains stable across temperature variations.
frozen7
Messages
163
Reaction score
0
A resistor is to have a constant resistance of 30(ohm), independent of temperature. For this, an aluminium resistor with resistance R1 at 0(celcius) is used in series with a carbon resistor with resistance R2 at 0(celcius). Evaluate R1 and R2, given that \alpha 1 is 3.9 x 10^-3 for aluminium and \alpha 2 is -0.5 x 10^-3 for carbon.

Can anyone give me some clues to solve this question? Thanks in advance.
 
Physics news on Phys.org
Start with the definition of alpha.
 
Resistances in series ...
there's a way to represent these with a single equivalent resistance ...
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Calculate the equivalent resistance
Replies
11
Views
2K
Total equivalent resistance of a combined circuit
Replies
7
Views
2K
Electric current and resistance question
Replies
2
Views
2K
Resistivity equation relating to equations for resistors
Replies
23
Views
2K
Calculating total resistance of a combination circuit
Replies
19
Views
7K
How to calculate the resistance in a combined circuit
Replies
4
Views
2K
How to calculate R1 and R2 in this RC circuit
Replies
3
Views
3K
How to solve this chain with Kirchhoff's laws?
Replies
18
Views
3K
How to calculate resistance in a combined circuit using V&I
Replies
4
Views
2K
How can I calculate the equivalent resistance of this circuit?
Replies
9
Views
2K

Hot Threads

Recent Insights

Back
Top