Hi I'm trying to make a circuit which uses the KTIR0821DS opto-coupler with phototransistor in order to detect whether a square on a card in light or dark, and output a high or low voltage accordingly.
Ultimately I aim to feed the output into a comparator in order to process a high or low final output. The included circuit is able to detect the difference between a light or dark square, however the difference in voltage is far too low to do anything with, only about .1 to .3 volts.
I have been trying (and trying and trying) to use a 741 op amp to amplify the voltage output, and therefore the difference in light or dark squares, but I have been having no progress at all. (I'm a bit of a novice with electronics but willing to learn.) I keep trying different ways of connecting the op amp to this circuit but nothing works.
Can't seem to upload attachments from my PC so I put the circuit on a file hosting site : PicFront - Card_Reader_Circuit.jpg
Ultimately I aim to feed the output into a comparator in order to process a high or low final output. The included circuit is able to detect the difference between a light or dark square, however the difference in voltage is far too low to do anything with, only about .1 to .3 volts.
I have been trying (and trying and trying) to use a 741 op amp to amplify the voltage output, and therefore the difference in light or dark squares, but I have been having no progress at all. (I'm a bit of a novice with electronics but willing to learn.) I keep trying different ways of connecting the op amp to this circuit but nothing works.
Can't seem to upload attachments from my PC so I put the circuit on a file hosting site : PicFront - Card_Reader_Circuit.jpg