Solving 0th-Order Circuit Equations with Two Variables

In summary, the conversation was about solving a circuit problem and the person was struggling with getting the correct answer. They were advised to write out the equations in a different form and after having an epiphany, they were able to solve the problem correctly with v1=162 and v2=200.
  • #1
pat666
709
0

Homework Statement



see attached

Homework Equations


The Attempt at a Solution



[tex]0=(v_1-128)/5-V_1/60-(v_2-V_1)/4 [/tex]
[tex]0=(v_2-v_1)/4-v_2/80-(v_2-320)/10 [/tex]
I obviously know what the answer should be from multisim but its not coming out. I've tried multiple combinations of this mainly just changing -s to +s because I can never get the current direction right for some reson.

Thanks

edit: the covered up resistor is a 10ohm
 

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  • #2
pat666 said:

Homework Statement



see attached

Homework Equations





The Attempt at a Solution



[tex]0=(v_1-128)/5-V_1/60-(v_2-V_1)/4 [/tex]
[tex]0=(v_2-v_1)/4-v_2/80-(v_2-320)/10 [/tex]
I obviously know what the answer should be from multisim but its not coming out. I've tried multiple combinations of this mainly just changing -s to +s because I can never get the current direction right for some reson.

Thanks

edit: the covered up resistor is a 10ohm

Yeah, your signs are kind of strange. I just write the sum of the currents out of a node is equal to zero. Don't do subtractions or whatever you are doing.

So your first equation should be:

(v1-V1)/5 + v1/60 + (v1-v2)/4 = 0

Write out both equations using this form, and see if it all solves up better...
 
  • #3
Yeah, I had an epiphany last night and started getting these right:)
(v1-128)/5 + v1/60 + (v1-v2)/4 = 0
(v2-V1)/4+v2/80+(v2-320)/10=0

v1=162
v2=320
 
  • #4
pat666 said:
Yeah, I had an epiphany last night and started getting these right:)
(v1-128)/5 + v1/60 + (v1-v2)/4 = 0
(v2-V1)/4+v2/80+(v2-320)/10=0

v1=162
v2=320

v2 looks wrong. V2 = 320V is the right side source, so v2 has to be less than 320V...
 
  • #5
oops that's a typo v2 cane out as 200V, I put it in Mathematica and it matched multisim so i assumed that I was correct.
 

FAQ: Solving 0th-Order Circuit Equations with Two Variables

What is a 0th-order circuit equation with two variables?

A 0th-order circuit equation with two variables refers to a basic circuit problem that involves two unknown variables, typically voltage and current. This type of problem is commonly encountered in introductory circuit analysis courses and can be solved using various techniques, such as Kirchhoff's laws and Ohm's law.

How do I solve a 0th-order circuit equation with two variables?

To solve a 0th-order circuit equation with two variables, you can use a systematic approach that involves setting up and solving equations based on Kirchhoff's laws and Ohm's law. This typically involves identifying the unknown variables, writing equations based on the known values and laws, and then solving for the unknown variables using algebraic manipulation.

What are the key components of a 0th-order circuit equation with two variables?

The key components of a 0th-order circuit equation with two variables are the two unknown variables (typically voltage and current) and the known values, such as resistances, sources, and circuit configurations. These components are essential in setting up and solving the equations needed to find the values of the unknown variables.

Can I use any method to solve a 0th-order circuit equation with two variables?

While there are various methods that can be used to solve a 0th-order circuit equation with two variables, such as nodal analysis and mesh analysis, it is recommended to use the method that is most suitable for the specific circuit problem. This may depend on the circuit configuration, known values, and personal preference.

What are some common mistakes to avoid when solving 0th-order circuit equations with two variables?

Some common mistakes to avoid when solving 0th-order circuit equations with two variables include forgetting to include all known values in the equations, not properly applying Kirchhoff's laws, and making algebraic errors when solving the equations. It is important to carefully check your work and make sure all steps are correctly followed to avoid these mistakes.

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