SILLY QUESTION : Charging nd Discharging of CR cricuits

Hey...guys..... can neone plz help me.....
i am totally confused abt this concept of charging nd discharging of the capacitors....

what does the term Q = Q0 e-t/RC represent ????
same is the case for current , power, energy and p.d.....

Plz help me anyone............

7 Answers

39
Pritish Chakraborty ·

Q is the instantaneous charge of the capacitor system or "charge at a specific instant of time". The term "RC" is the time constant of the capacitor. "t" is that specific instant of time. Q0 is the maximum amount of charge which can accumulate in the capacitor, or the limiting charge.
This expression occurs because capacitors react to current differently. An uncharged capacitor acts like a short circuit(as if the capacitor was never there, and it was just circuit wire) and a charged capacitor as an open circuit(fully charged capacitors block DC current, hence the circuit acts as if it is open).

1
venkateshan ·

All those things are understood....
but what does the term " Q0e-t/RC indicate?????????

39
Pritish Chakraborty ·

I said Q is the instantaneous charge of the capacitor system or "charge at a specific instant of time". And what is Q? Q = Q0e-t/RC

49
Subhomoy Bakshi ·

Qo is the maximum charge that can appear on the capacitor

e is the base to napierian logarithm

t gives the time variable

R and C are the values of equivalent resistance and capacitance of a circuit.

Q is the charge appearing on the capacitance at time t!!!

if this was what u wanted!!

cheers!!

1
venkateshan ·

thank you subhomoy.....
i just wanted to know whether Q is charge appearing on the capacitor or is it being discharged.....

thak you

49
Subhomoy Bakshi ·

wel coe

discount of m for discount of n !! hehehe!! :P

39
Pritish Chakraborty ·

Yaar agar yahi poochna tha why didn't you specify?
Q = Q0e-t/RC is the expression of instantaneous charge during charging of a capacitor.
Q = Q0(1 - e-t/RC) is the expression of instantaneous charge during discharging of a capacitor.

Both expressions point to delays in passage of current through a charging and discharging capacitor.

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