This paper presents a straightforward but interesting experimental method for p-n diode characterization. The method differs substantially from many approaches in diode characterization by offering much tighter control over the temperature and current variables. The method allows the determination of important diode constants such as temperature coefficient of voltage, bandgap and indicates the existence of a unique temperature, hypothesized to be absolute zero, at which the voltage-temperature characteristics of the diode converge under different constant diode currents. (Contains 5 figures.)