Hiii friends..we are making sugar juice clarity meter i.e.a ckt which detects turbidity of a sugar juice and displays it on LCD.
The principle we are using is scattering of light when it passes through the sugar juice..thiis scattering is propotional to turbidity of a solution..my doubt is how to measure scattering of light?which photo diode and photo detector should we use for this?
i think you should select the photo diode depending upon the rating you want.For example if the light used to measure the scattering is intense and you want to measure the minute variations in it after it passes through the juice then you should buy a very high sensitive photo diode.It all depends on how much sensitive you want your detector to be.Then a Google search for the required device should be enough.
thanks for ur suggestion ..we have selected some photo diodes and photo transistors..but our guide said we should use photo diode and photo transistor pair..do u suggest anything like this?which pair we should use?we are going to sense change in intensity of light..
I read some where that photo diodes are faster while photo transistors can detect more accurate changes in light intensity. may be your guide want to have both the qualities for your circuit.
Just see this link, may be helpful: **broken link removed**
thanks man ..its helpful..we have selected photo diode and photo transistor..now before starting to build the circuit..we want to design LDO power supply about 5 to 10 V..how to design it?which IC should we lokk for?