Characteristic Equation for Parallel Circuit with Current Source and 3 Elements

In summary: It often involves the transfer function of the circuit, which is the ratio of the output voltage to the input voltage.In summary, the conversation discusses finding the characteristic equation of a circuit with a current source and 3 elements in parallel: a resistor and 2 inductors. The current can be calculated using the equation i(t) = v(t)/R + iL1(t) + iL2(t). The attempt at a solution involves combining the inductors into one and questioning the use of a characteristic equation when the current source is a constant. The characteristic equation is the algebraic equation obtained by applying the Laplace transformation to the differential equation and often involves the transfer function of the circuit.
  • #1
losafojjog
3
0

Homework Statement



im trying to find the characteristic equation of a circuit with a current source and 3 elements all in parallel: a resistor and 2 inductors L1 and L2.

Homework Equations



i believe the current can be calculated as:
i(t) = v(t)/R + iL1(t) + iL2(t)

The Attempt at a Solution



is this anywhere close?
(1/R)dv/dt + 1/L1(v) + 1/L2(v) = 0
i guess i don't understand what is equated in a characteristic equation.
 
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  • #2
combine L1 and L2 in parallel into L_total (assuming you don't care mutal inductance), now you have one less component.
 
  • #3
Is the current source a constant source or one of a function of time? And how could you write iL1 and iL2 as though the two i's for both are the same? Is it given that the inductance of both are the same?
 
  • #4
losafojjog said:

Homework Statement



im trying to find the characteristic equation of a circuit with a current source and 3 elements all in parallel: a resistor and 2 inductors L1 and L2.

Homework Equations



i believe the current can be calculated as:
i(t) = v(t)/R + iL1(t) + iL2(t)

The Attempt at a Solution



is this anywhere close?
(1/R)dv/dt + 1/L1(v) + 1/L2(v) = 0
i guess i don't understand what is equated in a characteristic equation.

Unless your current source is a constant, its derivative is not zero. If the source is constant, both inductors will act as short circuits, so there is no voltage across the resistor and no dynamic equation.
The characteristic equation is the algebraic equation you obtain when you apply the Laplace transformation to your differential equation.
 

1. What is a characteristic equation?

A characteristic equation is a mathematical equation that relates the coefficients and roots of a polynomial equation. It is used to find the roots or solutions of a polynomial equation.

2. How is a characteristic equation different from a polynomial equation?

A polynomial equation is a general form of an equation, while a characteristic equation is specifically used to find the roots or solutions of a polynomial equation.

3. What is the significance of a characteristic equation in mathematics?

The characteristic equation is significant because it allows us to find the roots or solutions of a polynomial equation, which are important in various mathematical applications such as optimization, physics, and engineering.

4. How do you solve a characteristic equation?

To solve a characteristic equation, you first need to write the polynomial equation in standard form. Then, you can use various methods such as factoring, the quadratic formula, or the rational root theorem to find the roots of the polynomial. These roots will be the solutions to the characteristic equation.

5. Can a characteristic equation have complex roots?

Yes, a characteristic equation can have complex roots. Complex roots can occur when the polynomial equation has coefficients that are complex numbers, or when the polynomial has repeated roots. In these cases, the characteristic equation will also have complex roots.

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