Question

I have 36 discrete voltage levels and 60 discrete current levels how do i calculate the number of discrete power levels without repetition

Answer 1

is it just a combination with 96 choices from which i choose 2?

Answer 2

Since all of your voltage and currents are discrete, meaning they have no relation, and power = voltage * current, I would say you multiply each of your 36 voltages by each of the 60 individual currents.

Answer 3

but for example if i multiply 0.1mA*9V i get .9V but if i multiply 0.3mA with 3V i also get .9V since the power level is the same i don't want to count it twice

Answer 4

The power dissipated by the element may be the same as another element, but it is still discrete unless you are counting the same element twice.
And just for clarification, if you multiply 0.1mA*9V you get .9mW.

Answer 5

sorry my unit was incorrect i meant .1A

Answer 6

Okay, you still want to make sure you are writing watts and not volts for your unit of power.

Answer 7

right that unit is wrong too i meant W... but emphasizing similar results should be counted once

Answer 8

I'm not certain what you're trying to do outside of not having repeated values for your power, so if you are calculating them yourself, make a table and use hash marks for the individual results. You will end up with a table that you can take the unique power levels from.

Answer 9

why would a combination equation be incorrect

Answer 10

I don't know that it would be incorrect, you asked about discrete voltages and currents and I'm simply telling you that if your elements are discrete then their power dissipation is also discrete.
Are you doing a statistical, mathematical, or circuit analysis problem?

Answer 11

maybe it is misleading to use the word discrete? my context is the power supply can only supply whole number voltages and 1/10ths of an Amp i.e. 0, 1*0.01, 1*0.02... up to 36*6... I could maybe count a coupe and see what the formula for the series is without counting all of them?

Answer 12

I would think that permutations might be a better fit here, however if this is part of a standard exercise then it is best to stick with the subject they are trying to present.

Answer 13

this is part of the real life exercise where there's no particular chapter to reference from lol

Answer 14

Plot it.

Answer 15

i like that idea

Answer 16

You could use a program like matlab and do some matrix math and plot the results.

Answer 17

Unless one of these level 90+ have an idea.

Answer 18

i have a pwm signal capable of outputting maximum of 255 power levels so just looking at the numbers that is my limiting factor (not the power supply) in the pursuit of higher resolution and more control in a transfer function in a mechatronics class. I'm still interested in how to find the original question but i realize I don't have to as 255 selections is definitely less than the power supply's resolution...if it could call it resolution? -analog vs discrete and pursuing more analog-like control in an inherently discrete sysem

Answer 19

Well you are at least a year beyond me, I won't even play with emag until fall. :D

Answer 20

Short of doing a lot of work, I still think that matlab may be the best type of solution here. You could produce a graph and get a visual representation of the type of levels you are looking at.

Answer 21

i've got a vid of it in operation on my fb if you wanna see, maybe give you ideas of project or whatever you wanna build for senior project or builds that you want to bring into class Brent Higgins nice to meet you

Answer 22

Nice to meet you too Brent. Hopefully you will find someone here that is able to give you some real help. :)

Answer 23

actually looking at that video agian it's 0.01*36, 0.02*36.... all the way up to 6*36 where the voltage stays constant. All possible power levels are accounted for in the number of levels of current i.e. 0.01, 0.02, 0.03 so i just divide 6 by 0.01 that gives me 600 different power level options but that gets reduced to 255 bc the pwm can only differentiate that many

Answer 24

https://www.facebook.com/photo.php?v=10151643368820883&l=6351191912424400902

theres the vid

Answer 25

I was going to point that out, your voltage was staying constant in the video.

Answer 26

thanks, i'm writing up the report i'll post it on my site hopefully by the end of today brentghiggins.wordpress.com

Answer 27

I'll be interested to read and see what you guys were up to. :)