Help for building the circuitr

[NARENDRA1234]

I am making a photo detector circuit using LED and photo transistor.light of white LED is passed through solution and change in the intnsity is detected using photo transistor.so while choosing these components which important parameters should i considered.i am attaching the datasheets ,we have selected.Thanks in advance

 

[Siniša]

If you are detecting large change of transmittance on wide spectrum then these might work for you. If you are attempting to measure chemical solution concentration, source light and detector linearity is crucial. So if your solution has change of transmittance at particular wavelength, you could use stabilized light source at that particular wavelength and use detector with linear response at same wavelength.
Explaining what exactly are you trying to do would make it so much easier to help you...

 

[NARENDRA1234]

THNKS MAN...we are measuring turbidity of a solution ..so light intensity varies according to the turbidity of a solution..so we will be detecting this change in intensity..