Coupled RC circuits with AC current source

In summary, the conversation discusses a circuit with two capacitors and two resistors, and the goal is to find the voltage at R1 and R2 for an AC current. The person has made some progress but is unsure how to continue. They attempt to solve the problem using differential equations but are reminded that it is also possible to use impedances and phasor values. The discussion also addresses some errors in the attempt at a solution, including having voltage and current terms in the same equation.
  • #1
no_alone
32
0

Homework Statement


Hi, I already asked a question close to this, but now I have different conditions.
This is the circuit

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[itex] C_1 = C_2 \\
R_1= R_2[/itex]

The current is an AC , and I would like to know the voltage at R_1 and at R_2
I made some progress but I do not really know hot to continue.

The Attempt at a Solution

VR1 = VC1
VR1 + VRc - VC2 = 0
VR2 = VC2
IR1 + IC1 + VRC = Iinj
IRc = IR2 + VC2
[tex] V_1 = V_{C1} = V_{R1} \\ V_2 = V_{R2} = V_{C2} [/tex]

[tex] \frac{V_1}{R_1} + \frac{dV_1}{dt}*C_1 + \frac{V_{Rc}}{R_c} = I_{inj} \\
\frac{V_{Rc}}{R_c} = \frac{V_2}{R_2} + C_2*\frac{dV_2}{dt}\\
[/tex][tex] \frac{dV_1}{dt}*C_1 = I_{\omega} -\frac{V_1-V_2}{R_c} - \frac{V_1}{R_1} \\
\frac{dV_2}{dt}*C_2 = -\frac{V_2}{R_2} +\frac{V_1-V_2}{R_c} \\
--> C_1 == C_2 , R_1 == R_2 \\
\frac{dV_1}{dt} = \frac{I_{\omega}}{C_1} -\frac{V_1-V_2}{R_c*C_1} - \frac{V_1}{R_1*C_1} \\
\frac{dV_2}{dt} = -\frac{V_2}{R_1*C_1} +\frac{V_1-V_2}{R_c*C_1} \\

[/tex]
 
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  • #2
With AC sources you can obtain steady-state solutions for such circuits using impedances for the components and phasor values for the sources. No need to write or solve differential equations, the usual DC circuit methods and techniques of analysis will work fine.
 
  • #3
no_alone said:

The Attempt at a Solution


IR1 + IC1 + VRC = Iinj
IRc = IR2 + VC2
You can't have voltage and current terms in the same equation. Straightening this out is your first task.

It is perectly OK to use differential equations as you have done, especially if you never had phasors..
 

What is a coupled RC circuit with AC current source?

A coupled RC circuit with AC current source is an electrical circuit that consists of two or more resistors (R) and capacitors (C) connected together in a series or parallel configuration, and is powered by an alternating current (AC) source. In a coupled circuit, the components are connected together in a way that allows the energy to be shared or transferred between them, creating a dynamic system that responds to changes in the AC source.

What is the purpose of using a coupled RC circuit with AC current source?

The purpose of using a coupled RC circuit with AC current source is to filter or modify the AC signal. The capacitors in the circuit act as frequency-dependent reactances, allowing certain frequencies of the AC signal to pass through while blocking others. By adjusting the values of the resistors and capacitors, the circuit can be designed to attenuate or amplify specific frequencies, making it useful for applications such as audio signal processing and radio frequency (RF) communication.

How does a coupled RC circuit with AC current source affect the phase of the AC signal?

A coupled RC circuit with AC current source can introduce a phase shift in the AC signal. The capacitive reactance (Xc) and resistive reactance (R) in the circuit create a voltage divider, which affects the amplitude and phase of the output voltage relative to the input voltage. The amount of phase shift depends on the values of the components and the frequency of the AC source.

What are the key differences between a series and parallel coupled RC circuit with AC current source?

One key difference between a series and parallel coupled RC circuit with AC current source is the way the components are connected. In a series circuit, the resistors and capacitors are connected in a single loop, while in a parallel circuit, they are connected in multiple branches. This affects the overall impedance of the circuit, as well as the frequency response. In a series circuit, the total impedance is the sum of the individual impedance values, while in a parallel circuit, the total impedance is less than the individual values.

How can I calculate the frequency response of a coupled RC circuit with AC current source?

The frequency response of a coupled RC circuit with AC current source can be calculated using the transfer function, which is the ratio of the output voltage to the input voltage. This can be determined by analyzing the impedance of the circuit at different frequencies. The transfer function can also be graphed on a frequency response plot, which shows the amplitude and phase of the output voltage at different frequencies.

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