greetings all,
ok heres the issue, I'm trying to build a light sensor for my robot, I have a pretty good desogn with a 741 diferentiator circuit, the only problem is that I want to have it from just a standard DC powers supply. However I don't know and can't find anywhere on how to wire it so I get the neccesary -9v on pin 4. All the wireing diagrams I've found just say to have a -v but dont actualy say how to obtain it.
What kind of light sensor are you using? At what level are you going to set the comparator threshold? If the threshold is going to be above +3V, you shouldn't need a negative supply rail.
If you need a negative supply voltage for other parts of your circuit, you could use a charge pump inverter such as the venerable TC7660.
Consider using a comparator such as LM393 (it's also a very popular part).
Depending on what's the hatched rectangle, you could get very different circuits. I basically refuse to guess if the author isn't willing to give minimal information.
sorry, forgot to label it, thats a light sensor. the LDRs I've found are too expensive and i got a bunch of solar lights during the last "everywatt counts" sale at home depot so I'm trying to use those.
Thanks for the tip about the single source opamp I found some good material.