## thermal noise

The noise generated by thermal agitation of electrons in a conductor. The noise power, *P*, in watts, is given by *P* = k*T**f*, where k is Boltzmann’s constant in joules per kelvin, *T* is the conductor temperature in kelvins, and *f* is the bandwidth in hertz. *Note 1:* Thermal noise power, per hertz, is equal throughout the frequency spectrum, depending only on k and *T*. * Note 2:* For the general case, the above definition may be held to apply to charge carriers in any type of conducting medium. *Synonym* **Johnson noise.**