Electronics - Time Response of Reactive Circuits - Discussion

1. 

What voltage will the capacitor charge up to in the given circuit for the single input pulse shown?

[A]. 3.15 V
[B]. 4.3 V
[C]. 4.75 V
[D]. 4.9 V

Answer: Option B

Explanation:

No answer description available for this question.

Phaneendra said: (Feb 14, 2011)  
f=1/RC
Toff=1/f
Ton+Toff=T;32.4+16.2=48.6
Ton/T=Von(drop)
beacause we hav calucalate voltge during on state .

V-Von=4.3v
5-0.66=4.3v

Elkaa said: (Mar 26, 2011)  
Dear,

If the timeconstant = RC is 16.4 usec, and the pulse is 32.4 usec, then I would expect that the capacitor charges up to Vin, as it has a lot more time then RC.

Please confirm.

Sreekumar said: (Jul 16, 2011)  
I agree with Elkaa, it will charge upto Vin.

Nitesh said: (Sep 13, 2011)  
Vc(voltage across capacitor) = V0(1-e-t/to)

Vasu said: (Oct 13, 2011)  
Can anyone explain this in brief please.

Ganesh said: (Apr 21, 2012)  
I agree with elka.

Mehta said: (Apr 25, 2012)  
Elkaa is totally wrong. It takes 5 timeconstant to charge upto Vin.
So it won't charge upto Vin.
Nitesh is right. In that equation substitute t = 32.8us and to = RC = 16.4us.

Leena said: (Jun 22, 2013)  
Writing the kirchoff's current law you get Vin-iR-(1/C) inetgral (idt).

On applying the laplace transform we get the equation,
Vo(1-e-t/to).

On substituting we get 4.3.

Where to = 1/RC.
Vo = 5.

Arun said: (Oct 29, 2013)  
@Mehta is right. Given circuit is a low pass filter circuit.

So output voltage is:

Vo = Vin (1-e^(-t/RC)).

T = 32.8 us.

R = 82 k.

C = 200 PF.

Gaurav said: (Jan 16, 2016)  
T constant = rc = 82 k x 200 pf = 16.4 micro sec.

Plus time = 32.8 micro sec.

Trc = 32.8/16.4 = 2.

1 Trc = 63.3%.

2 Trc = 86%.

So, output voltage = 5x(86/100) = 4.3 v.

Padma said: (Aug 31, 2016)  
Yeah! @Gaurav is absolutely right.

Prabhu said: (Nov 24, 2016)  
@Gaurav.

Please explain about the 1 trc and 2 Trc calculation.

Seema said: (May 7, 2017)  
Yeah! Please explain about 1trc and 2trc calculation.

Kanha said: (Jul 7, 2017)  
(1-e^(-t/RC))=0.63 for t=RC and it is 0.86 for t = 2RC.

Asha said: (Jul 20, 2017)  
Thank you @Gaurav.

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