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Investigating LDRs

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Investigating LDRs A light dependent resistor is a resister that depends on the amount of light shining on it. Introduction I will be investigating how much of a current that flows through the resistor depends on the amount of light that is shining on the LDR. Planning My prediction for this coursework is that the more the further that I move the LDR from the light the weaker the current will be on the milliammeter. Equipment The equipment that I will be using will be: Milliammter LDR Cell (battery) Meter Ruler Lamp Power Pack 4 Leads Component Clip Method Step by Step I will be working in a pair. I will set up a circuit that will measure the amount of light that will shin on the LDR.I will be taking 8 reading of different distances. ...read more.


The only thing that will change is the distance from the LDR to the light. Here is a table that shows the distances I will be using: Distance (cm) 1 5cm 2 10cm 3 15cm 4 20cm 5 25cm 6 30cm 7 35cm 8 40cm Here is a diagram that show how a LDR works: Here is a picture of the circuit I will be using: Here is a table of my results: Distance (cm) Current test 1 (MA) Current test 2 (MA) Current Test 3 (MA) 1 5cm 9.3 9.3 9.3 2 10cm 5.3 5.3 5.3 3 15cm 3.4 3.4 3.4 4 20cm 2.4 2.4 2.4 5 25cm 2 2 2 6 30cm 1.4 1.4 1.4 7 35cm 1.2 1.2 1.2 8 40cm 1.1 1.1 1.1 This table show that I have made my distance correct and I have read the readings on the milliammeter accurately. ...read more.


I think that the test went good because my result come out correct that is because I made it a fair test. I took 24 reading all together and put it into a line graph. I found out that my predication was correct and that the further away the LDR is from the light the less current there is. My original finding and conclusion were correct see last section for details. My results are accurate because I carried out a fair test, which then allowed my recording to be accurate. I had one anomalous result, which did not fit into the pattern maybe it was because there was a little big of light in the back ground so the reading did not come out correct. If I would improve my investigation I would have done more readings to make it an even fairer test and I could have compared my result with other peoples results. ?? ?? ?? ?? Tamar Amin Page Physics coursework ...read more.

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