Need help finding unique resistor combinations

AI Thread Summary
The discussion revolves around finding 17 unique resistor combinations using 3-ohm, 5-ohm, and 10-ohm resistors to meet specified voltage and current requirements. The resistors must be of different values, and combinations can be arranged in series or parallel. Participants suggest creating a table to explore all possible combinations, including single resistors, pairs in parallel, pairs in series, and mixed configurations. The goal is to calculate equivalent resistances and match them to the given voltage and current ranges. This approach will help identify valid combinations that satisfy the problem's constraints.
tiger00
Messages
2
Reaction score
0
Need help finding unique resistor combinations!

Homework Statement



Amps = 30, 45, 60, 70
Voltage = 600 to 700, 600 to 800, 400 to 600
I have three typres of resistors 3 ohm, 5 ohm, 10 ohm
I have to find 17 combinations of resistors to work with the given amps and volts. The resistors all have to be differnet values(you can't use 2-3 ohm resistors, 2-5 ohm resistors or 2-10 ohm resistors.) The resistors can be in parallel or in a series.

Homework Equations



I=V/R
 
Physics news on Phys.org


tiger00 said:

Homework Statement



Amps = 30, 45, 60, 70
Voltage = 600 to 700, 600 to 800, 400 to 600
I have three typres of resistors 3 ohm, 5 ohm, 10 ohm
I have to find 17 combinations of resistors to work with the given amps and volts. The resistors all have to be differnet values(you can't use 2-3 ohm resistors, 2-5 ohm resistors or 2-10 ohm resistors.) The resistors can be in parallel or in a series.

Homework Equations



I=V/R

Welcome to PF.

Sorry, I don't really understand your problem. What 17 combinations? I only see 12 combinations of voltage ranges and currents. Maybe if you could supply more information?
 


That is my issue too...the teacher gave us the three different voltage ranges, the 4 different amperages, and we were told that we can use 3, 5, and 10 ohm resistors. She said that we have to find 17 combinations of using the resistors. Ex. I could use a 3,5,10 ohm resistor one time in a series. I could use a 3,5,10 the next time in parallel...as long as the I=V/R hold true...
 


tiger00 said:
That is my issue too...the teacher gave us the three different voltage ranges, the 4 different amperages, and we were told that we can use 3, 5, and 10 ohm resistors. She said that we have to find 17 combinations of using the resistors. Ex. I could use a 3,5,10 ohm resistor one time in a series. I could use a 3,5,10 the next time in parallel...as long as the I=V/R hold true...

In that case then just make a table of all the resistor combinations you can make. You have 3 single resistors alone, you have 3 pairs in ||, 3 pairs in series alone, you have 3 more with 1 in || 2 in series, etc. Basically all combinations possible.

Then figure the equivalent resistances that each makes, and see which ones fit which V and I.
 
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...
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...
Back
Top