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| − | ==Voltage Divider==
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| − | [http://en.wikipedia.org/wiki/Voltage_divider Wikepedia]
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| − | Derivation from Ohm's Law
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| − | ==IR Distance==
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| − | ===Reflective Optical Sensor===
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| − | The reflective optical sensor ( Datasheet ) consists of an infrared LED, labelled "E" for Emitter on the diagrand and on the package, and a phototransistor that passes an amount of current proportional to the reflected light received. The phototransistor is labelled "S" for Sensor. The one leg of the sensor is connected to +5V, which supplies current, and the voltage drop across the 10k resistor that we measure is proportional to the amount of current.
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| − | There is a continuous voltage response for objects over a short range of proximity to the sensor. The response is not linear. Linearity can be approximated by the log of the log of the signal.
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| − | <center>
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| − | [[Image:optical.png]]
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| − | </center>
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| − | ==Hall Effect==
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| − | [http://www.sensorwiki.org/index.php/Hall_effect Hall Effect] on Sensorwiki.org
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| − | <center>
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| − | [[PID_2007]]
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| − | </center>
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