Circuit Analysis: Parallel Series component failure.


Joined Apr 26, 2005
You can blame whatever you want. The truth is, you are human and will make mistakes. Reading too fast is one. Not identifying the real problem is one, and failing to exercise due diligence is one. Of course, that is why I recommended that course of you could do a self-assessment on why you were incorrect. Good job.


Joined Sep 13, 2015
you have to calculate the current when the circuit is working properly. (R3+R4)//R2 = 1.79K. That means V2 = 1.79K / (1K+1.79K)*100 = 64.2v.

So the circuit is working properly at 64.2v. and I3=I4=64.2/(4.7+5)=6.6ma.

For I3=12.77ma, something must have shorted out on R3+R4.

If you were to short R3, R4//R2 = 1.53K. V2=1.53K/(1.53K+1K)*100=60.4V, and I3=I4 = 60.4v/5K=12.09ma != 12.77ma.

If you were to short R4, R3//R2 = 1.50K. V2=1.50K/(1.50K+1K)*100=60.0V, and I3=I4 = 60.0V/4.7K=12.77ma. Bingo!