I am building an amplifier for a phototransistor, and it works well under normal lighting conditions. However, in my application the light is very dim and barely produce any readable output. I tried to increase the feedback resistance potentiometer (R1 in the schematic) from 50k to 1M Ohm and it gave me the gain I wanted but the noise was very high and it was prone to EMI from a nearby power supply. My question is, would the noise decrease if I used a two amplifiers in a multistage configuration?

Op amp used: OP07DD

Phototransistor: Osram SFH3310

Thanks.

I am building an amplifier for a phototransistor. It works well under normal lighting conditions.

In my application, the light is very dim and barely produce any readable output. 

I tried to increase the feedback resistance potentiometer (R1 in the schematic) from 50k to 1M Ohm and it gave me the gain I wanted but the noise was very high and it was prone to EMI from a nearby power supply.

Would the noise decrease if I used two amplifiers in a multistage configuration?

• Op amp used: OP07DD
• Phototransistor: Osram SFH3310