Home▸Electromagnetism▸RL Circuit: Self-Inductance & Current Transients

RL Circuit: Self-Inductance & Current Transients

Interactive 3D RL circuit: watch current rise and decay through a real solenoid coil as you flip the switch, tune voltage, resistance and inductance, and see the exponential I(t) = (V/R)(1-e^(-tR/L)) law play out live with a growing/collapsing magnetic field.

Electromagnetism3DModerate60 FPS📱 Mobile-adapted⇄ 2D version

Every real coil — a motor winding, a relay, a transformer, a solenoid — resists sudden changes in current because of its own self-inductance. This simulator renders an actual 3D solenoid wired into a battery-resistor-switch loop: close the switch and the current climbs smoothly toward V/R along the exponential curve I(t) = (V/R)(1 − e^(−tR/L)); open it and the coil's collapsing magnetic field drives the same current back down to zero. Tune the voltage, resistance and inductance to see the time constant τ = L/R stretch or compress the transient live, watch charge markers move along the wire at a rate proportional to the instantaneous current, and see the magnetic field arrows inside the coil grow and collapse with it — exactly the physics behind why switching off an inductive load without a flyback diode can spike the voltage.

⚙ Under the hood

Interactive 3D RL circuit with a real solenoid coil: flip the switch to charge or discharge the inductor and watch the current follow the exponential law I(t) = (V/R)(1-e^(-tR/L)) while the magnetic field grows or collapses live.

electromagnetisminductanceRL circuitFaraday's lawsolenoidtransient

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install