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# Aubuchon Joseph Lab 1

last edited by 5 years, 2 months 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.

Using Red Led I must have 100 ohms of resistance to limit the current to 30 ma at 5 volts

How do you get this??

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.

This is the minimum resistance, if the resistance was lowered the led would likely fail

c. What is the resistance range of the potentiometer?

from .05 ohms to 9.5 kohms

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

no, in a series circuit it doesn't matter where the resistors and leds are located because the current is equal all throughout.

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

350 ohms is what is required to protect the led from failure.

It is almost right, but the correct answer is :

Vtotal = Vresister + Vled

9 volts= Vresister + 2volts

Vresister = 7 volts

Vresister=IR

7 = 25mA * R

R = 280 Ohms (minimum resistance)