Electronics - Capacitors - Discussion

Discussion Forum : Capacitors - General Questions (Q.No. 20)
20.
After a capacitor has charged for 1 tc, what percentage of current remains in the resistor?
63.2
36.8
13.5
5.0
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
17 comments Page 1 of 2.

Trxapeut said:   5 years ago
It = It(1-e^-t/T).
t=time,
T= time constant ,
It = total current.

If t = -T then It=I(1-e^-1),
It=0.632It ;
It-0.632It = 0.368It = 36.8% of current.

Ashu k said:   6 years ago
If capacitor charges by 1tc (time constant).

Vc=V(1-e^-t/rc).

Here, t = 1 rc.
=> Vc=V(1-e^-1).
=> Vc=63.6.

Therefore % of current remained in resistor = 100 - 63.6.
= 36.8%.
(1)

Ali said:   7 years ago
What the value of V how it disappeared from the equation?

Dufe said:   9 years ago
I was thought with voltage and not current.

Does it mean one can define time constant in terms of current?

Aryaan said:   9 years ago
But current remain same in series RC charging circuit.

I think it is voltages instead of current, 1tc = 63.2% of full voltages and at that time the voltages across the resistor are 36.8%.

So, it is voltages. If anyone agree with me?

Ria said:   1 decade ago
@Archana,
e^-1 = 0.3678.

1-0.3678 = 0.6322.
= 63.2.

Archana Sasikumar said:   1 decade ago
How this V(1-e^-1) become 63.6? Can you please explain.

Pujitha said:   1 decade ago
If capacitor charges by 1tc(time constant).

Vc=V(1-e^-t/rc).

Here, t = 1 rc.
=> Vc=V(1-e^-1).
=> Vc=63.6.

Therefore,% of current remained in resistor = 100 - 63.6.

= 36.8%.

Jagat said:   1 decade ago
100% - 63.2% = 36.8 %..........
very simple

Shireen said:   1 decade ago
Capacitor charges upto 63. 2% of its final value in one tc. So 36.8% remaining. Hence current remaining in resistor is 36.8%.


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