A sine wave voltage is applied across a capacitor. When the frequency of the voltage is decreased, what happens to the current?

1 Answer
Jun 23, 2015

If the frequency of voltage is decreased, then current value is also color(blue)(decreased).

Explanation:

If the opposition to applied voltage is increased, then current value is decreased.

Here,the opposition is due to reactance of capacitor.

X_c=1/(2pifC)

X_c=reactance of capacitor,

f=frequency of applied voltage.

X_cprop1/f[since1/(2piC)=constant]" "color(blue)((1))

From ohm's law,

V=I_cX_c

X_c=V/I_c

X_cprop1/I_c[since V is constant]" "color(blue)((2))

From " "color(blue)((1))&color(blue)((2));

1/fprop1/I_C

color(green)(I_cpropf)

From above relation,

If the frequency of voltage is decreased, then current value is also color(blue)(decreased).