# Transimpedance amplifier with biopotentials

I have a PPG sensor to be specific the sensor is called " easy pulse finger sensor " which is a ( phototransisitor), can it be connected to a transimpedance amplifier ( current to voltage converter)?! Because the output of the sensor as i assumed will be a current, so i should amplify and convert it to voltage inorder to put it into bandpass filter

• Sure, you can connect it to a TIA. What's your question? – Douwe66 Feb 12 '17 at 8:09
• My question is how do i design a proper TIA suitable for my signal – Osama khalid Al Takhayneh Feb 12 '17 at 12:39

## 1 Answer

To read out a photo diode you can indeed very well use a TIA.

Wikipedia tells all the information you need to design a circuit. Find a suitable operational amplifier with a low input referred noise (just search for low noise opamp).

The formula for the output voltage is simply:

$$\frac{V_{out}}{I_P} = -R_f$$

The output voltage is buffered by the amplifier so you can directly filter it in the way you want it.