diode current calculator
Calculate diode current from voltage using the Shockley equation or piecewise practical model. Enter Vd, Is, n, and T to get forward or reverse current (A).
reverse saturation current calculator
Calculates the current in a diode given the voltage using the precise Shockley equation and provides a convenient piecewise useful model of reverse leakage and high-current series-resistance characteristics.
Formula & Table Summary:
Id = Is * (exp( Vd / (n * Vt) ) - 1) Vt = k * T / q (≈25.85 mV at 300 K)
Inputs: Vd (V), Is (A), n (1–2), T (K). Output: Id (A).
diode current calculator
Input the diode voltage ( V d ), saturation current ( Is ), ideality factor ( n ) and temperature ( T ) to calculate diode current based on the Shockley equation. When used as a junction diode, also includes the effects of reverse leakage and series-resistance effects as parametric variations.This Diode Current Calculator solves a diode junction voltage (Vd) to diode current (Id) using the Shockley diode equation and approximate practical piecewise versions. Circuit analysis, bias calculation and fast leakage/or forward conduction estimates can be done with this tool. Warning: exponentials which are extremely large can be numerically unstable; usually bound by voltage range or logarithmic processing in use. When it comes to power dissipation, the product of returned Id and Vd is the diode dissipation (W).
semiconductor diode current
| Vd (V) | Is (A) | n | T (K) | Id (A) |
|---|---|---|---|---|
| 0.0 | 1e-12 | 1.0 | 300 | -1.00e-12 |
| 0.2 | 1e-12 | 1.0 | 300 | 3.27e-05 |
| 0.6 | 1e-12 | 1.5 | 300 | 0.0112 |
| 0.7 | 5e-12 | 1.2 | 300 | 0.128 |
| -5.0 | 1e-12 | 1.0 | 300 | -1.00e-12 |
Frequently Asked Questions - diode current calculator:
What is the Shockley diode equation?
Id = Is (e^{Vd/(nVt)} - 1), where Vt = kT/q is the thermal voltage.
What is saturation current Is?
Is is the diode reverse saturation current — a tiny leakage current when the diode is reverse biased.
What is the ideality factor n?
n (typically 1–2) models recombination and ideality; 1 for ideal diffusion-limited diodes, ~2 when recombination dominates.
How do I compute thermal voltage Vt?
Vt = kT/q. At 300 K, Vt ≈ 25.85 mV.
How to handle reverse bias?
Before breakdown, reverse current ≈ −Is (small leakage). At breakdown voltage the simple model no longer applies.
What about series resistance Rs?
At high forward currents, series resistance limits current; modify the model: Vd ≈ nVt ln(Id/Is+1) + Id Rs and solve numerically for Id.
Can the exponential overflow numerically?
Yes—at larger Vd the exponent can overflow. Use logarithmic math or limit Vd in calculators to avoid numeric overflow.
How to get power dissipation?
Multiply Id × Vd to get diode power dissipation (W) for thermal checks.
Are these values valid for LEDs and Schottky diodes?
Shockley is a general model but parameters differ: LEDs/Schottkys have different Is, n, and Rs. Use device datasheet parameters for accuracy.
How to get Is and n for a specific diode?
Use the diode datasheet, or fit measured I–V data (log-Id vs Vd) to extract Is and n via curve fitting.
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