# Exponential converter notes

At the bottom of this page (xonik.no) is the ultimate best series of articles I found about exponential converters (parts: 1, 2, 3, 4). This is a collection of my notes so that I remember the key points about how I understood the whole topic.

The whole idea of exponential conversion is based on the Ebers-Moll equation:

$${Ic = Is \cdot e^{\frac{V_{BE}}{V_{T}}} }$$

Here ${I_{S}}$ and ${V_{T}}$ are constants, so in a certain range around 0.7V base voltage, the collector current is exponential to the voltage difference between the base and the emitter (${V_{BE}}$) of the transistor.