Device physicsMVP
Diode I–V explorer
The ideal (Shockley) diode I–V curve, I = Is(exp(V/nVt) − 1), as you vary the parameters.
Inputs
Ideal Shockley model
Educational ideal-diode model. It omits series resistance, high-injection, recombination, and breakdown, so the current rises unrealistically fast at high forward bias.
A
Current at 0.8 V (Vt = 25.86 mV)
27080 mA
Interpretation
A diode conducts negligibly until the forward voltage approaches its turn-on “knee”, then current rises exponentially (a factor of ~10 every n·Vt·ln10 ≈ 60 mV per decade at 300 K for n = 1). A larger saturation current or ideality factor, or higher temperature, shifts and softens the knee. This ideal model exaggerates high-bias current because it has no series resistance.
Formula
I = Is · (exp(V / (n·Vt)) − 1)
Vt = kT/q.
Variables
| Symbol | Variable | Unit |
|---|---|---|
| I | Diode current | A |
| Is | Saturation current | A |
| V | Forward voltage | V |
| n | Ideality factor | dimensionless |
| Vt | Thermal voltage (kT/q) | V |
Assumptions & validity
This tool assumes:
- Ideal Shockley diode; operating in forward bias.
- No series resistance, high-injection, recombination, or breakdown.
Worked example
Is = 1×10⁻¹² A, n = 1, 27 °C.
At 0.6 V, I ≈ Is·exp(0.6/0.0259) ≈ a few mA.