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Lab 1 Report_Lucas Faria

Page history last edited by Lucas Faria 7 years ago

2. Controlling the Brightness of LEDs


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.

 Hint: Make sure that you account for the forward voltage drop (Vf) of the LED that you're using.


Using red LED

Vf = 2.00[V]

Power Supply supplies exactly 5.00[V]

R = (5.00 - 2.00)[V]/30[mA]

R = 100.00[Ω] 


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.


It is a minimum resistance. It is needed more current flowing to make the LED likely fail, so we should decrease the resistance (lower).


c. What is the resistance range of the potentiometer?

Accordingly to digit multimeter:

Range of the potentiometer = [50 : 9617][Ω]

-0.5 ?


3. Basic LED Circuit with Switch 


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


No, it does not matter. Because the current and the voltage on each components will be the same independent of circuit are arranged.



4. Battery-Powered LED with Switch on Breadboard


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


Vf = 2.00[V]

Power Supply supplies exactly 9.00[V]

Limit current 30[mA]

R = (9.00 - 2.00)[V]/30[mA]

R = 233.33[Ω]


5. Make a Video of Your LED Being Switched On and Off.

Comments (2)

Vivien Tsao said

at 9:37 pm on Jul 11, 2013

-1: missing video :(

Good job! :]

Lucas Faria said

at 4:04 pm on Jul 17, 2013

It wasn't ready. Sorry. It's ready right now tho! ;)

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