In a p–n junction diode, change in temperature due to heating

${\mathrm{R}}_{\mathrm{diode}}= \frac{{\mathrm{V}}_{\mathrm{supply}}-{\mathrm{V}}_{\mathrm{diode}}}{{\mathrm{I}}_{\mathrm{diode}}}$

The increase in temperature due to heating decreases both the forward resistance and reverse resistance, and consequently increases the instantaneous diode current, which means that heating changes the entire V−I characteristics of a p-n junction diode.