I need help in figuring out the amperage of the 5V supply.
I also want to know what the output voltage would be like and what the transistor is doing there. Thanks
URGENT
You would only need a low current supply, a 78L05 should be more than enough - on a quick glance the transistor looks to be a common base amplifier?. Presumably the text explains it all?.
The transistor (Q1) allows a single supply to be used. The op amp input and output are at the same voltage level, only the pulse from the opto is amplified. If the 510 ohm resistor were directly connected to the op amp, the output DC would be very difficult to control.
what i meant was like this circuit will have a different vout as the current on the photodiode varies right. so i can, measure the voltage recorded under different sources of light cant i?otherwise wht youre saying is that this will always give a constant voltage indepedant of the the intensity?
just one question, the current between the photodiode and the inverting input of the opamp, would it be in the direction of the photdiode or the opamp.
and this current would be alternating right? otherwise the capacitor would not let it pass through.
If you chop the light, the signal can pass thru a coupling capacitor. Making a stable DC amplifier is difficult, but an AC amplifier is easy. The schematic in the appbrief is AC coupled.
SO the incident light causes a photocurrent that goes and gets all its DC components taken off and then goes on to the inverting input and the output is V+ + V- which then is partially fed back via the feedback circuit and gets amplified.
Correct me if i wrong.
Thanks guys, I dint know anything about this. Thats why i chose such a project.