@@ -27,6 +27,6 @@ A quick teardown of a ~$20 500BL from Walgreens revealed no integrated photonics
## Operational Theory
Pulse oximetry is based on the [Beer-Lambert law](https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law), a principle that relates the concentration of a species to the attenuation of light through a sample:
```math
I=I_in*e^{-(D*C*\epsilon)}
I=I_{in}e^{-(DC\epsilon)}
```
where $`I`$ is the intensity of light transmitted through the sample; $`I_in`$ is the intensity of the light prior to absorption by the sample; $`D`$ is the optical path length; $`C`$ is the solute concentration; and $`\epsilon`$ is the extinction coefficient, the sample's absorption at a given wavelength of light.
