Voltage across switch in LR circuit as switch is opened?

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SUMMARY

The discussion centers on the behavior of voltage across a switch in an LR circuit when the switch is opened. Initially, the voltage at the right side of the switch is perceived to be zero when closed, but upon opening, the induced electromotive force (emf) due to the inductor causes a voltage spike, represented as εL. The voltage across the open switch is calculated as ε - εL, leading to confusion regarding the relationship between resistance values R1 and RL and their impact on voltage levels across the switch.

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nikodym
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Moved from a technical forum, so homework template missing
egOw5dN.jpg

1. I thought that when switch was closed, voltage at the right side of switch was 0 and long time after the switch is open, the voltage at the right side of the switch becomes 0.
2. After the switch is open ecause of the inductor, voltage at the right side of the switch is εL = induced emf
So voltage across the open switch = ε -εL

Is there any thing wrong with my thought1 and2?
I don't understand why voltage across the switch becomes greater if R1 is greater than RL.

Thanks for any help in advance:)
 

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Hello Nikodym, :welcome:

Hard to read but it looks as if the battery voltage is some kind of ##g##. If the switch is closed for a while, where does that drop to the 0 you expect in step 1 ?

What do you mean with ##\varepsilon## ? Are you aware of the relationship between current and voltage for an induction L ?
 

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