# /Deprecated/-TechReport: Non-inverting PD AMP

## Background
* We decide to [adopt SFH250v(PD) with Photoconductive mode](https://hackmd.io/T4rIt80oQL-H5OBRAHPRDQ?view#Solution)
* [Understanding Photovoltaic and Photoconductive Modes of Photodiode Operation](https://tinyurl.com/mr3n822d)

## Problem

* We **have to add Negative voltage rail for PD bias**

## Solution

* ~~I refer to [here](https://electronics.stackexchange.com/questions/510775/photodiode-amplifier-circuits-why-use-an-op-amp-instead-of-just-a-resistor)~~
* ~~Maybe this problem can be solved when I adopt non-inverting AMP circuit~~
* inversing 1st PD I/V stage + inversing 2nd amp stage = positive

## Evolution

## Deprecated
* Reason: non-invert seems to be easy and enough

###### tags: `TechReport` `DeWei`