Question

Why does rise time increases if capacitor value is increased

Answer 1

I understand that increasing current decreases the time taken for a capacitor to both charge and discharge, and also increasing the potential difference and charge increase the time taken for a capacitor to charge while decreasing the time taken for it to discharge.

However, I am having troubles with deducing what effect resistance will have on it? Is it as simple as V = IR, and increasing resistance with a constant potential difference will decrease current (and thus increase the time taken for a capacitor to both charge and discharge?)












When a capacitor with capacitance CC is charged by applying a voltage source VV in series with a resistance RR, the voltage VcapVcap of the capacitor (and thus charge) increases according
Vcap=V[1−exp(−t/RC)]
Vcap=V[1−exp⁡(−t/RC)]
Thus, as expected, the charging time of the capacitor increases with increasing RR.

The discharge has the same time constant RCRC
Vcap=V[exp(−t/RC)]