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Patil Uday Lab 1

Page history last edited by zahraa@... 5 years, 2 months ago

Uday Patil

EE 47 Lab 1


Question 2

a. What resistance do you need to limit current to 30 mA (if using red LED) or 25 mA (if using yellow or green)? Be sure to state which color LED you are using. This resistance refers to the total resistance in series with the LED.

5V - 1.85Vf = 3.15Vr

V/I = R

3.15Vr/0.03A = 105Ω

The resistance needs to be 105Ω to limit the current to 30mA for the red LED.


b. Is the resistance from question (a) a maximum or minimum resistance? That is, in which direction if you change the resistance (higher or lower) would the LED likely fail.


The resistance is the minimum resistance to prevent the LED from burning out. If the resistance was lowered, then the LED would most likely fail.


c. What is the resistance range of the potentiometer?


The resistance range of the potentiometer is 0-10 kΩ


Question 3


a. Does it matter what order the components of your circuit are arranged between power and ground? Why or why not?


It doesn't matter because the electricity flows through all of them with the same voltage and current according to Kirchoff's Law. The only thing that matters is the orientation of the LED because it is a diode so only allows electricity in one direction.

Question 4


a. Using this battery, what is the minimum resistance required for use with your LED?


9V - 1.85Vf = 7.15 Vr

V/I = R

7.15Vr/0.03A = 238.3Ω

The minimum resistance wen using a battery is 238.3Ω for the red LED.


LED Video

Comments (1)

zahraa@... said

at 4:36 pm on Jul 6, 2015

Great Job

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