Creating a RL/RC/RLC Circuit model

[BeefBowl]

Hello! Would someone here guide me in creating a model for a RL/RC/RLC circuit? I have started studying this topic in advanced but I don't quite understand the concept in DE.
I have watched videos from youtube.com and they solve problems using EE such as V=IR. And yes, I am able to answer problems too using theoretical formulas from my EE class. What I want to know is how to apply DE in this topic. I really want to learn this soon because maybe next week, we are going to start on this topic.
Thanks!:tongue:

 

[BeefBowl]

Anyone?

 

[HallsofIvy]

Your question is really too vague to give a complete answer. Exactly how you model such a circuit as a differential equation depends on exactly what the circuit is like.

The basic ideas are
1) The total voltage change around a circuit is 0.
2) The voltage drop over a resistor is Ri where i is the current and R the resistance.
3) The voltage drop through a coil is L di/dt where i is the current and L the inductance.
4) The voltatge drop through a capacitor is Q/C where Q is the charge and C is the capacitance (you will have to ask an electrical engineer why C is divided and not multiplied).

Since current is the rate of change of charge, i= dQ/dt and so di/dt= d^2Q/dt^2 and the voltage drop through a resistor is R(dQ/dt) and the voltage change through a coil is L(d^2Q/dt^2).

Since those are all "drops" (negative change in voltage), there must be voltage supplied to the circuit for the total change to be 0. Adding those for a circuit that has all three kinds of objects and setting it equal to the voltage supplied gives you a second degree differential equation for Q.

(It is not a good idea to "bump" a thread after only 8 minutes. That can get you banned!)

 

[BeefBowl]

Thanks! I get it now! Thank you very much physicsforum and HallsofIvy!

 

[blue_raver22]

Hi there,

Creating a RL/RC/RLC circuit model can be a challenging but rewarding task. First, it's important to understand the basic concepts of differential equations (DE) and how they apply to circuits. DE is a mathematical tool used to describe the behavior of dynamic systems, such as electrical circuits. In this context, DE helps us to understand how the voltages and currents in a circuit change over time.

To create a model for a RL/RC/RLC circuit, you will need to use Kirchhoff's laws and Ohm's law to set up a system of equations that describe the behavior of the circuit. This involves writing out the equations for the voltage drops across each component and the current flowing through each component. You can then use DE to solve these equations and determine the behavior of the circuit over time.

It's great that you have already watched videos and solved problems using EE concepts like V=IR. This will be helpful in understanding the underlying principles of circuit analysis. To apply DE in this topic, you will need to use some additional concepts, such as inductance and capacitance, to fully describe the circuit behavior.

I suggest studying the basics of DE and its application to circuits before delving into the RL/RC/RLC circuit model. This will give you a solid foundation to understand the mathematical concepts involved. Additionally, practicing solving problems using DE will help you become more comfortable with the topic.

I hope this helps guide you in creating your RL/RC/RLC circuit model. Best of luck in your studies!