Calculadora de Ruido Johnson-Nyquist
Calcula la tensión y potencia de ruido térmico (Johnson-Nyquist) de resistencias a temperatura dada.
Fórmula
V_n = √(4kTRB)
Cómo Funciona
Johnson-Nyquist thermal noise is a fundamental phenomenon in electronic systems where electrical components generate random voltage or current fluctuations due to the thermal agitation of charge carriers. At any temperature above absolute zero, the random motion of electrons in a conductor creates spontaneous voltage variations, which appear as electrical noise. This noise is directly proportional to temperature and the resistance of the component, and is independent of the specific material's composition.
Ejemplo Resuelto
Calculate the Johnson-Nyquist thermal noise for a 1 kΩ resistor at room temperature (290K). Using the formula V_n = √(4kTRΔf), where k = Boltzmann constant (1.38 × 10^-23 J/K), T = temperature (290K), R = resistance (1000 Ω), and Δf = bandwidth (1 Hz), we get: V_n = √(4 * 1.38 × 10^-23 * 290 * 1000 * 1) = 4.05 × 10^-9 V or 4.05 nV
Consejos Prácticos
- ✓Always consider thermal noise when designing low-signal analog circuits
- ✓Minimize noise by reducing resistor values and operating temperature
- ✓Use low-noise amplifiers for sensitive measurements
- ✓Consider noise figure when selecting electronic components
Errores Comunes
- ✗Ignoring thermal noise in high-impedance circuits
- ✗Assuming all noise sources are equal
- ✗Not accounting for temperature variations
- ✗Overlooking bandwidth effects on noise calculation
Preguntas Frecuentes
What is Johnson-Nyquist thermal noise?
A fundamental electronic noise generated by thermal agitation of charge carriers in a conductor, creating random voltage fluctuations.
How does temperature affect thermal noise?
Thermal noise increases directly with temperature - higher temperatures result in greater electron motion and increased noise voltage.
Can thermal noise be completely eliminated?
No, it's a fundamental physical phenomenon that exists at any temperature above absolute zero.
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