Optical Sensors

Optical Sensors.

Optical Sensors

Experiment 1
Design a system to solve problem 6.12. Prove your design using circuit simulation. Create a title block with a title and your name


1. Reference the textbook problem 6.12. Design a system using the photoconductive cell in Figure 6.9 to measure and display light intensity. Make the design such that 20 to 100 mW/cm2 produces an output of .2 to 1.0 V. What is the readout error when the intensity is 60 mW/cm2?

2. Reference the textbook problem 6.14. A single silicon photovoltaic cell is found to have an open-circuit voltage of 0.6 V and a short-circuit current of 15 mA in full sunlight. Show how a collection of these cells can be arranged to deliver 500mW at 9.0V into a load. Write a verbal description of your solution.

3. Reference the textbook problem 6.20. In a turbidity system such as that of Figure 6.34, the tanks are 2 m in length. A laser with a 2.2-mrad divergence, 2.1-mW power, and 1-mm exit radius is employed. If the sample nominally detracts from the beam power by 12% per meter, find the intensity of the beam at the detector. The laser is 1.5 m from the beam splitter. Note that the splitter halves the power and does not affect the divergence.

4. Reference the textbook problem S6.2. An automatic security camera must operate as follows when an intrusion occurs: 1. If the ambient light level is greater than 20mW/cm2, the shutter is activated. 2. If the ambient light is less than 20mW/cm2 a light source is triggered. 3. When the source lighting reaches 20mW/cm2, the shutter is triggered. Design the system and signal conditioning using the following assumptions:

a. The shutter and light source are triggered by TTL logic high signals.
b. A CdS cell with characteristics given in Figure 6.9 is used to monitor ambient light level.
c. A photodiode with the characteristics given in Figure 6.16b will be used to measure light intensity after the light source is triggered. Explain why the CdS cell could not be used here also.

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Optical Sensors

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