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RL current after a step calculator
Estimate inductor current and voltage after a constant source-voltage step.
On this page
Inductor current0.76A
Inductor voltage4.41V
Time constant0.01s
Calculator controls
How to calculate
Estimate inductor current and voltage after a constant source-voltage step.
Inductor current =
Vs/R+(I0-Vs/R)*exp(-t/(L/(1000*R))) AInductor voltage =
Vs-R*(Vs/R+(I0-Vs/R)*exp(-t/(L/(1000*R)))) VTime constant =
L/(1000*R) sWorked example
- Resistance (Ω): 10
- Inductance (mH): 100
- Final source voltage (V): 12
- Initial inductor current (A): 0
- Elapsed time (s): 0.01
- Inductor current: 0.76 A
- Inductor voltage: 4.41 V
- Time constant: 0.01 s
Assumptions and limits
This is an ideal educational model. Enter quantities in the stated SI units; it does not certify equipment safety or real operating limits. Uses a linear ideal inductor and resistor with no saturation or parasitic elements.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate inductor current and voltage after a constant source-voltage step. The current approaches source voltage divided by resistance; the time constant is inductance divided by resistance.
When this tool is useful
The current approaches source voltage divided by resistance; the time constant is inductance divided by resistance.
Understanding your inputs
| Input | Example |
|---|---|
Resistance (Ω) R | 10 |
Inductance (mH) L | 100 |
Final source voltage (V) Vs | 12 |
Initial inductor current (A) I0 | 0 |
Elapsed time (s) t | 0.01 |
Frequently asked questions
Which assumptions matter for this result?
This is an ideal educational model. Enter quantities in the stated SI units; it does not certify equipment safety or real operating limits. Uses a linear ideal inductor and resistor with no saturation or parasitic elements.
How can I check the worked example?
Use the displayed example inputs in the stated formula. Keep each quantity in its labelled unit and compare the unrounded result before applying display rounding.