Inductor Circuit Simulation: Understanding Current Rise and Voltage Output

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Discussion Overview

The discussion revolves around understanding the behavior of an inductor circuit during simulation, specifically focusing on the current rise and voltage output. Participants explore the transient response of the circuit and the equations governing its behavior.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant expresses confusion about the inductor current not showing a gradual increase from 0A to 500mA as expected.
  • Another participant questions the waveform being referenced and requests equations to describe the circuit's behavior.
  • A third participant mentions the time constant of the circuit, calculated as L1/R1 = 10μs, suggesting that the current may not rise as slowly as initially thought.
  • A participant provides an equation for the inductor current and demonstrates that substituting values yields a result of 0.5A, which aligns with their expectations.
  • Another participant suggests examining the initial transient waveform to better understand the LR time constant.
  • A final participant provides specific simulation settings to observe the current rise over approximately 50μs.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the expected behavior of the inductor current waveform, with some expressing confusion and others providing different insights into the circuit's dynamics.

Contextual Notes

There are references to specific circuit parameters and simulation settings, but the discussion does not resolve the initial confusion regarding the waveform behavior or the gradual increase of current.

PhysicsTest
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TL;DR
To understand the inductor circuit.
I am trying to understanding the inductor circuit. I have drawn the below circuit and try to simulate
1635602554158.png

The Inductor current comes to 500mA and Vout is 5V as per simulation. The current in inductor should slowly increase from 0A to 500mA but i cannot see that in the waveform. Is my understanding correct?
 
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PhysicsTest said:
but i cannot see that in the waveform
Neither can we. What waveform ?
Do you have some equations to describe the behaviour of your circuit ?

##\ ##
 
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I'm not sure about "slowly".
The time constant for this circuit is L1/R1 = 10uSec.
 
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1635604571909.png

This is the output waveform i can get. Ok now i started writing the equation for the circuit.
##i(t) = \frac{V} {R} (1 - e^{\frac{-Rt} L})##
Substituting the values
##i(1) = 5/10*(1 - e^{-10^5}) ##
##i = 0.5A##. The answer is matching.
 
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So zoom into the first few us of the transient waveform to see the LR time constant...
 
The DC analysis sets up 500 mA before the run.
You must use; V1 pulse; initial=0V; Von=5V; Tdelay=5usec;
and .TRAN stop time = 100 usec.
Then see the current rise over about 50 usec.
Inductor.png
 
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