Shot Noise Calculator
Enter average current and bandwidth. The Shot Noise Calculator instantly computes RMS shot noise current, relative noise, and NEP for detectors.
About the Shot Noise Calculator
The Shot Noise Calculator is a precise, scientifically accurate tool that computes the fundamental shot noise in electrical currents and photon detection — the quantum limit arising from the discrete nature of electrons and photons. This Shot Noise Calculator implements the exact formula i_shot = √(2 e I Δf), where e is electron charge, I is average current, and Δf is bandwidth. Proudly supported by Agri Care Hub.
Scientific Formula
Relative Noise: ΔI/I = √(2 e Δf / I)
Noise Equivalent Power (NEP): NEP = hν √(2 I_ph / (e η)) / √Δf (for photodetectors)
e = 1.602 × 10⁻¹⁹ C
Why This Calculator Is Essential
Shot noise is the ultimate limit in: • Photodetector sensitivity • Low-light imaging and astronomy • Precision current measurement • Quantum optics experiments • Radiation detection • Electron microscopy It sets the standard quantum limit (SQL) — no classical current has less noise than shot noise for the same average.
How to Use
- Enter average DC current I in amperes (e.g., 1e-9 for 1 nA).
- Enter measurement bandwidth Δf in Hz.
- Click “Calculate Shot Noise”.
- Get RMS noise current and relative noise level.
When Should You Use This Tool?
- Photodetector design and sensitivity analysis
- Low-noise electronics
- Astronomical instrument specification
- Quantum optics and single-photon detection
- Radiation dosimeter calibration
- Teaching quantum noise limits
Scientific Foundation
Shot noise was discovered by Walter Schottky in 1918 and arises from the Poisson statistics of discrete charge carriers. The formula i_shot = √(2 e I Δf) is exact for full shot noise (e.g., vacuum tubes, photodiodes). In semiconductors, it can be suppressed (partition noise). Full theory at Shot Noise on Wikipedia and all quantum optics and electronics textbooks.
Conclusion
The Shot Noise Calculator brings the fundamental quantum noise limit to your browser — with perfect accuracy and beautiful design. Whether you’re a student learning quantum limits, a researcher designing ultra-sensitive detectors, or an engineer specifying low-noise electronics, this tool delivers precise results every time. For more quantum tools, visit Agri Care Hub.