Solving Transient Response RL Circuit with Switch

In summary, the question is asking if when the switch is closed, there is no current flowing through the right side of the circuit (the resistor and diode). The answer is no, because the current through the diode increases when the switch is closed.
  • #1
van123
2
0

Homework Statement


I have a circuit containing an inductor, 2 resistors and diode in series however there is also a switch.




The Attempt at a Solution



I thought that when the switch is closed there would be no current flowing through the right side of the circuit (resistor and diode) and therefore for part a) the time constant is L/R=10/20=0.5ms and steady state inductor current is just V/R=0.5A.
However, this can't be the case in order to do the show that question in part C), so I was wondering if someone could just explain the circuit to me when the switch is open and closed. Thank you!
 

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  • #2
What, in toto, is the question?
Never mind, I got the picture straightened out. Stand by ...
 
Last edited:
  • #3
How it works: at t=0 swirch S is closed and the current thru the inductor increases. At t = 0.5ms S opens and the inductor current continues thru the diode until iL = 0 at t = TZ. The current stays at zero until S closes again, at which point the cycle repeats.

How about doing (b)?

Part (c) is misleadingly stated. The current thru the diode is -10 mA only if the switch stays open for a long time.

(d) is an important computation. You will need it for part (e).

Part (f) is more challenging because the current thru the diode does not ever equal zero.
 
  • #4
Reattempt

Thank you rude man so much for explaining, i have tried to answer the entire question again from what I (hope) i now understand. If you have time could you perhaps see my answers and tell me if I'm still not getting it?
Thanks again!
 
  • #5
van123 said:
Thank you rude man so much for explaining, i have tried to answer the entire question again from what I (hope) i now understand. If you have time could you perhaps see my answers and tell me if I'm still not getting it?
Thanks again!

Certainly. I await your submission.
 

Related to Solving Transient Response RL Circuit with Switch

1. How do you solve a transient response RL circuit with a switch?

To solve a transient response RL circuit with a switch, you need to follow the following steps:

  • 1. Determine the values of the inductance (L) and resistance (R) in the circuit.
  • 2. Draw the circuit diagram and label all the components.
  • 3. Use Kirchhoff's laws to write the differential equation for the circuit.
  • 4. Solve the differential equation to get the expression for the current in the circuit.
  • 5. Substitute the values of L, R, and the initial conditions into the expression to get the final equation for the current.

2. What is a transient response RL circuit with a switch?

A transient response RL circuit with a switch is a type of circuit that contains a resistor (R) and an inductor (L) in series, with a switch connected in parallel to the inductor. When the switch is open, the circuit behaves as a simple RL circuit, but when the switch is closed, the circuit experiences a transient response as the current changes over time due to the inductor's energy storage.

3. What is a transient response in an RL circuit?

A transient response in an RL circuit is a temporary response that occurs when a sudden change (such as the closing or opening of a switch) is applied to the circuit. This causes the current to change over time as the inductor resists changes in the current flow, creating a transient response.

4. How do you calculate the time constant in a transient response RL circuit?

The time constant (τ) in a transient response RL circuit can be calculated using the formula τ = L/R, where L is the inductance in henries and R is the resistance in ohms. This value represents the time it takes for the current in the circuit to reach 63.2% of its final value.

5. What is the final value theorem for a transient response RL circuit?

The final value theorem for a transient response RL circuit states that as time approaches infinity, the current in the circuit will approach a steady-state value equal to the voltage divided by the resistance (I∞ = V/R). This means that after a long enough period of time, the transient effects of the inductor will dissipate, and the circuit will behave as a simple RL circuit with a constant current flow.

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