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Unformatted text preview: requirements—attach a copy of the spec sheet describing the sensor and circle the specs on the sheet to show that the requirements are met. 3) A circuit with a light dependent resistor (LDR) and an LED in series is shown below. Let the resistance of the LDR be R1 and the resistance of the LED1 be R2 VCC 6V LED1 LDR Derive an expression for the current flowing through LED1 and the time varying resistance R1. Why does R1 change with time? How does the current in LED1 change with changes in R1? How does the LED’s current affect the LED brightness 4. A voltage divider circuit is shown below with a resistor R1, LDR and LED. Let the resistance of the LDR be R2 and the resistance of the LED be R3, VCC 6V R1 1.0k Ω LDR LED Derive an expression for the voltage across the LED. How does the voltage across the LED change with changes in R2?...
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This note was uploaded on 09/18/2011 for the course ME 140L taught by Professor Staff during the Fall '09 term at University of Texas at Austin.
- Fall '09