I'm trying to measure the thermal white noise generated by chemical batteries. So far I've measured the current noise, the voltage noise (V noise) and the bandwidth (delta v). From the equation below, I'm trying to solve the equation for the frequency. The problem is that there's an exponential expression in it. But it gets worse, the frequency f is in it. http://s24.postimg.org/jbunj5z1h/Vnoise.jpg All I could come up with is to put hf/kt on one side of the equation and I'm stuck with ln (4hfr delta v / V^2). Do you have a solution?