# LED shortage

#### ShayanK1996

Joined Feb 2, 2016
2
Hi Guys!

I was hoping if any of you guys could explain to me on how you would know which LED goes bad when the voltage drops. (part c in the attachement)

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#### dl324

Joined Mar 30, 2015
15,846
Welcome to AAC!

For homework, students are expected to show their work and Users will guide them to a solution.

Also post the values from the parameter file.

#### ShayanK1996

Joined Feb 2, 2016
2
Welcome to AAC!

For homework, students are expected to show their work and Users will guide them to a solution.

Also post the values from the parameter file.
VT = 0.25 V

Ig = 5 mA

Is1 = 30.72106 nA

Is2 = 10.30577 pA

Is3 = 562.6759 pA

Vgc = 7 V

I just need to understand the concept on how voltage is affects LED shortage.

#### dl324

Joined Mar 30, 2015
15,846
Use the formula for calculating the forward voltage of each diode. Then add them together and see how that compares to Vgc.

What would the voltage across a shorted LED be?

#### hp1729

Joined Nov 23, 2015
2,304
Hi Guys!

I was hoping if any of you guys could explain to me on how you would know which LED goes bad when the voltage drops. (part c in the attachement)
Build it. I doesn't have to be LEDs. Resistors in series, same thing.