## [SOLVED] help needed on photocells please.

now, i am doing the same planning excersise as einstein was--->
 Quote by einstein2603 you are required to design a laboratory experiment to investigate how the output from a photocell depends on its distance from a point source of infra-red radiation. pay particular attention to: 1. the procedure to be followed 2. how the output of the photocell would be measured 3. range of distances to be used 4. ranges of measuring distances uesd 5. any relevant circuit diagrams 6. any safety precautions 7. particular features which ensure the accuracy and reliability of the results 8. diagram of apperatus
and i was wondering, do you think that it would be enough to do the experiment you mentioned earlier where you just attatch a DVM on mA setting to the photocell, or whether it would give more of a valid conclusion to do the thing where you put a resistor and a voltage divider [?] into the circuit and measure the voltage?

 Quote by Hootenanny Analogue means that the data can take any of an infitie number of values. Digitial can only take two values, 1 or 0 on / off. An example of an analogue wave would be a sine or cosine curve. ~H
yea that's what i thought, but it says to plug the circuit into analogue in on the circuit diagram [half way down the page that the other guy gave me a link for]...where is that wire going. or do i not even need to know...
 One thing to watch out for is the example posted on the last page is for a light dependent resistor, a standard LDR will not react to IR as its wavelength is too long, this means the only thing it will do is react to visable light, You can in theory get LDR's that respond to IR (think they are, Ge:Cu)but you need to use components you can source
 Will you please help im confused Ive been told by my physics tutor to connect the photocell to a battery, and take a reading of the current. Would this work? THANX
 could you help me with the apparatud that will be used for this experiment
 Ok heres my take on things. I am also doing this experiment and whil it seemed a bit strange at first its not so bad. Really just asking berkemen and hootenanny whether what ive done is the right sort of lines. A few people have mentioned batteries. however having done a bit of reading on photocells i thought they generated current themselves, so ive left out a battery. By the way not sure if anybody has acctually clarified this. We dont acctually do the experiment, just plan it. my plan is to have the photocell connected to a fixed resistor with a large resistance, and to measure the voltage acroos that large resistance. From that i could work out the current using simple maths. think thats right but just a yes or no would help enormously

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 Quote by welshdragon Will you please help im confused Ive been told by my physics tutor to connect the photocell to a battery, and take a reading of the current. Would this work? THANX
Yes, this should work but you may only obtain a limited range of data.

~H

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