Hello attached is the circuit diagram of a simple photo diode and amplifier circuit i have built. The op amp is a single supply LTC1050 chopper stabilized op amp, and the photo-diode is a BPW24R . I am powering the op amp off a 9v Battery.
The problem with my circuit is that it all works fine untill the power supply is turned off, when it turns back on i am getting an offset voltage Typically 9V) on the output (hooked up to an oscilloscope), the only way to rectify this problem is if i disconnect the feedback loop and reconnect again, all of a sudden the offset is gone and the circuit is working fine again. Having to put a switch in the feedback loop seems a bit of a hack.
Also if i fully saturate the photodiode (enough so without the offset it would max out the amplifier at 9v) the problem also then goes away, has anyone any ideas as to how to rectify this. I have tried decoupling capacitors on the power supply to no avail.
See link to circuit diagram https://skydrive.live.com/redir?resid=10CDA58407A779C1!16567&authkey=!AAQempVIe3j42E8
The problem with my circuit is that it all works fine untill the power supply is turned off, when it turns back on i am getting an offset voltage Typically 9V) on the output (hooked up to an oscilloscope), the only way to rectify this problem is if i disconnect the feedback loop and reconnect again, all of a sudden the offset is gone and the circuit is working fine again. Having to put a switch in the feedback loop seems a bit of a hack.
Also if i fully saturate the photodiode (enough so without the offset it would max out the amplifier at 9v) the problem also then goes away, has anyone any ideas as to how to rectify this. I have tried decoupling capacitors on the power supply to no avail.
See link to circuit diagram https://skydrive.live.com/redir?resid=10CDA58407A779C1!16567&authkey=!AAQempVIe3j42E8