fogl
Junior Member level 1
I connected the photodiode (current source) as shown:
If i measure the voltage across + and - input of op. amp. i don't get 0V, but the voltage rises proportional to current from current source. How is that possible? Rolling Eyes The op. amp. is TLC2272 and Vcc is 5V. I get 0.35V across at 2.5mA current and 0.46V at 2.6mA.
The aim of this circuit is to measure the solar radiation, which is proportional to short circuit current of photodiode. But if the voltage at - input of op. amp. rises, this is no more short circuit current i am measuring.
If i measure the voltage across + and - input of op. amp. i don't get 0V, but the voltage rises proportional to current from current source. How is that possible? Rolling Eyes The op. amp. is TLC2272 and Vcc is 5V. I get 0.35V across at 2.5mA current and 0.46V at 2.6mA.
The aim of this circuit is to measure the solar radiation, which is proportional to short circuit current of photodiode. But if the voltage at - input of op. amp. rises, this is no more short circuit current i am measuring.