Home
Back
Thermal Noise Power Equation:
| From: | To: |
Thermal noise, also known as Johnson-Nyquist noise, is the electronic noise generated by the thermal agitation of charge carriers (usually electrons) inside an electrical conductor at equilibrium. It's a fundamental noise source in all electronic circuits.
The calculator uses the thermal noise power equation:
Where:
Explanation: The equation shows that thermal noise power is directly proportional to both temperature and bandwidth.
Details: Understanding thermal noise is crucial for designing sensitive electronic systems, communication systems, and any application where signal-to-noise ratio is important. It sets the fundamental limit for the minimum detectable signal.
Tips: Enter temperature in Kelvin and bandwidth in Hertz. Both values must be positive numbers. The result will be displayed in scientific notation due to the typically very small values.
Q1: What is Boltzmann's constant?
A: Boltzmann's constant (k) relates the average kinetic energy of particles in a gas with the temperature of the gas. Its value is approximately 1.38 × 10-23 J/K.
Q2: How does temperature affect thermal noise?
A: Thermal noise increases linearly with temperature. Higher temperatures mean more thermal agitation of electrons, resulting in greater noise power.
Q3: Why is bandwidth important in thermal noise?
A: Thermal noise is spread uniformly across all frequencies (white noise), so the total noise power is proportional to the bandwidth of the system.
Q4: Can thermal noise be eliminated?
A: No, thermal noise is a fundamental physical phenomenon. It can only be reduced by lowering the temperature or reducing the bandwidth.
Q5: What is the noise voltage equivalent?
A: For a resistor R, the noise voltage can be calculated as \( V_n = \sqrt{4kT R \Delta f} \).