What Happens to Current Direction in an RL Circuit When the Switch is Opened?

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SUMMARY

The discussion focuses on the behavior of current in an RL circuit when the switch is opened after being closed for a long time. Specifically, it concludes that the direction of the current in the right-hand loop containing the inductor (L), resistor R2, and resistor R3 is counterclockwise immediately after the switch is opened. The participants clarify that while there is current flowing through the inductor before the switch is opened, the inductor maintains the current flow in the same direction when the switch is opened, resulting in a counterclockwise current in the specified loop.

PREREQUISITES
  • Understanding of RL circuits and their components (inductors and resistors)
  • Familiarity with circuit analysis techniques, including Kirchhoff's laws
  • Knowledge of the behavior of inductors in response to changes in current
  • Basic principles of electromagnetism related to current flow
NEXT STEPS
  • Study the application of Kirchhoff's voltage law in RL circuits
  • Learn about the time constant in RL circuits and its effects on current flow
  • Explore the concept of back EMF in inductors when the circuit is interrupted
  • Investigate the transient response of RL circuits when switches are opened or closed
USEFUL FOR

Electrical engineering students, educators teaching circuit theory, and hobbyists working with RL circuits who want to deepen their understanding of current behavior during switch operations.

syhpui2
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Homework Statement



A circuit made with a battery, a switch, an inductor. and three resistors is shown in the figure. To begin with, switch S has been open for a long time. Then at time t = 0 the switch is closed.

http://i.imgur.com/ws5UD.png
ws5UD.png


After being closed for a long time, the switch S is now opened.
What is the direction of the current in the right hand loop containing L, R2 and R3 immediately after the switch is opened?

(a) clockwise
(b) counterclockwise Correct Answer

Homework Equations



Ampere's law?

The Attempt at a Solution



I am not sure how do I ind the direction of current if switch is opened? Should be no current?

Thx
 
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Before the switch is opened, what currents are flowing and in what directions?
 
gneill said:
Before the switch is opened, what currents are flowing and in what directions?

There are current on r2,r3 and inductor and it is clockwise...
 
syhpui2 said:
There are current on r2,r3 and inductor and it is clockwise...

No, that's not right. Yes, there is current through the inductor, but what is that current and what is the voltage across the inductor? What about R1?
 

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