Circuit Analysis: Parallel Series component failure.

JoeJester

Joined Apr 26, 2005
4,390
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 action....so you could do a self-assessment on why you were incorrect. Good job.
 

dannyf

Joined Sep 13, 2015
2,197
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!
 
Top