Solving RC Circuit Pulse with Step-by-Step Approach

In summary, the conversation involved a student seeking help with a homework problem that required a step-by-step approach. The student had made a mistake and was unsure of the correct solution. The expert advised the student to recalculate the constants and also consider the response for t > 1s.
  • #1
DefaultName
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0
Hi, I have this problem to do for HW. I did what it asked for, or so I think. I think I may have made a mistake somewhere, it's telling me its not correct. Can you check it out?

BTW, I have to use the step by step approach. I'm assuming my solution will be v(t) = K1 + K2 * e^(-t/RC).
I then find V(infinity), V(0+) and V(0-), Rthevenin.

http://img240.imageshack.us/img240/6569/untitledzn8.png
 
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  • #2
DefaultName said:
Hi, I have this problem to do for HW. I did what it asked for, or so I think. I think I may have made a mistake somewhere, it's telling me its not correct. Can you check it out?

BTW, I have to use the step by step approach. I'm assuming my solution will be v(t) = K1 + K2 * e^(-t/RC).
I then find V(infinity), V(0+) and V(0-), Rthevenin.

http://img240.imageshack.us/img240/6569/untitledzn8.png

V(0+) = V(0-) = 0. The input pulse does not charge the capacitor instantly. Only an impulse can do that.
 
Last edited by a moderator:
  • #3
ah I see, we haven't hit impulses yet. Is the rest correct?
 
  • #4
DefaultName said:
ah I see, we haven't hit impulses yet. Is the rest correct?

You must recalculate the constants K1 and K2 for the correct initial condition.
And you must calculate the response for t > 1s.
 

1. How do you calculate the time constant in an RC circuit?

The time constant in an RC circuit is calculated by multiplying the resistance (R) in ohms by the capacitance (C) in farads. The resulting value is measured in seconds and represents the time it takes for the circuit to reach 63.2% of its final charge or discharge. The formula for calculating the time constant is τ = RC.

2. What is the step-by-step approach for solving an RC circuit with a pulse input?

The step-by-step approach for solving an RC circuit with a pulse input involves breaking the circuit into two parts: the charging phase and the discharging phase. In the charging phase, the capacitor charges up to the input voltage with the help of the resistor. In the discharging phase, the capacitor discharges through the resistor until it reaches 0V. By analyzing the circuit during these two phases, you can determine the voltage and current at any given time.

3. How do you calculate the voltage across the capacitor in an RC circuit with a pulse input?

The voltage across the capacitor in an RC circuit with a pulse input can be calculated using the formula Vc = Vp(1-e^(-t/RC)), where Vp is the peak input voltage, t is the time in seconds, R is the resistance in ohms, and C is the capacitance in farads. This formula takes into account both the charging and discharging phases of the circuit and can be used to determine the voltage at any time during the pulse.

4. What is the significance of the time constant in an RC circuit?

The time constant in an RC circuit is important because it determines the speed at which the circuit will charge or discharge. A smaller time constant means the circuit will reach its final voltage faster, while a larger time constant means it will take longer. The time constant also affects the shape of the voltage and current curves in the circuit, with a larger time constant resulting in a more gradual change.

5. Can you use the step-by-step approach to solve RC circuits with other input signals?

Yes, the step-by-step approach can be applied to solve RC circuits with other input signals, such as square waves or sine waves. The key is to break the circuit into different phases and analyze the voltage and current at each phase separately. The calculations may be more complex, but the same principles apply. It is also possible to use circuit analysis software to simulate the behavior of RC circuits with different input signals.

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