# What is Thermal Noise Power and Voltage ?

Thermal noise power and thermal voltage are important parameters in electrical and electronic engineering because they have several practical implications and applications. The calculator and formula helps to assess noise level in a system which is needed to maintain high SNR (Signal to Noise Ratio) to ensure quality of the signal being transmitted by transmitter or processed by receiver. In wireless communication systems, knowing thermal noise power is essential to design receivers and communication channels. In high frequency applications, thermal noise is significant factor and it has to be estimated while designing RF and microwave devices or components.

Thermal noise power is the random noise generated by thermal motion of electrons in a conductor. It is also known as Johnson-Nyquist noise.

The thermal voltage is a voltage noise generated by thermal motion of electrons in a resistor. It is also known as thermal noise voltage. Thermal noise is directly related to temperature. By measuring the thermal noise voltage across a resistor, it's possible to indirectly measure the temperature.

## KTB Thermal Noise Power Formula

It can be expressed or calculated using following formula.
➨ P =K*T*B

To calculate thermal noise power, just provide values of temperature (T) and bandwidth (B) of the system and calculator will provide thermal noise power as output. K is boltzmann's constant with value of 1.38 x 10-38 J/K which is already used inside for calculations.

## Thermal noise power calculator | KTB Calculator

Provide input as per example values or your desired ones and click on "Calculate" button to get the output.

Temperature in Kelvin (Input1) :

Bandwidth of system in Hz (Input2) :

Thermal Noise Power in dBm (Output) :

EXAMPLE:
INPUTS: T = 300 Kelvin, BW=1000 Hz
OUTPUTS: Thermal Noise power = -143.82 dBm
Please note that temperature (Kelvin) = Temperature(Celsius) + 273.16

## Thermal Noise Voltage Formula

It can be calculated using following formula.
Vthermal noise voltage = (4*R*k*T*B)0.5

To calculate thermal voltage , just provide values of resistance of resistor (R), temperature (T) and bandwidth (B) into the calculator and it will provide thermal noise voltage as output by click of a button. K is boltzmann's constant with value of 1.38 x 10-38 J/K which is already used inside for calculations.

## Thermal voltage calculator

Input temperature, resistance and bandwidth and click "Calculate" button to get thermal voltage as output.

Temperature in Kelvin (Input1) :

Resistance in Ohm (Input2) :

Bandwidth of system in Hz (Input3) :

Thermal Noise Voltage Volt (rms) (Output):

EXAMPLE:
INPUTS: T = 291 Kelvin, Resistance =50 , BW=1Hz
OUTPUTS: Noise voltage= 8.964e-10 volt or 0.0008964 µV
Please note that temperature(Kelvin) =Temperature(Celsius) + 273.16

Conclusion : Thermal noise power and thermal voltage calculators and formulas provide precise quantification of electrical noise inherent in electronic circuits. By understanding the relationships between temperature, bandwidth and resistance in noise generation, these tools empower professionals across various fields, from communication systems design to quantum electronics