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Rodrigo Ornelas Lab1

Page history last edited by Benjamin Tee 8 years, 1 month ago


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.

Super Bright Green Voltage =2.2 V



V=5v- 2.2v=2.8v

2.8v/0.025A=112 ohms


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 because I=V/R, so I is inversely proportional to R. If R were smaller, I would be bigger. According to the data sheets the max current is 25mA; a lower resitance would cause I higher than that and consequently a LED failure.

c) What is the resistance range of the potentiometer?

0.280 ohms to  10202 ohms (checked with multimeter)


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

No, because they are in series and the only thing that matters is that the circuit is complete, unlike parellel circuits. 


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

V= 9.0v-2.2v=6.8v


R=6.8v/.025A=272 Ohms


a) I could not find a battery because all of them were taken, so I set the power supply to 9v (the same Voltage of the missing battery)

Comments (1)

Benjamin Tee said

at 12:59 pm on Jul 14, 2012

Good job! Keep it up Ornelas!

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