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last edited by 8 years, 2 months ago

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.

I used YELLOW LED.

V= 5V, I=0.025 A, Vled= 2.0V

V=IR

(5-2.0)V=R*0.025A

R=120 Ohm

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 the minimum resistance that allows the maximum current to pass through LED without being failed. Decreasing R causes current to increase and exceed the limit so the LED fails.

c. What is the resistance range of the potentiometer?

from 0 to 10k Ohm

3-

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

Order of the component does not matter  in a closed circuit.The resistor will be resisting to current whether it is placed before the LED or after.

✔ The main reason is because the circuit is in series so the current flowing in and out is the same no matter what order.

4-

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

For the yellow LED and a battery

V=9V, Vled=2.0V, I=0.025A

V=IR

(9-2.0)V= 0.025A*R

R=280 Ohm

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