Physics 1308 Quiz 6
Physics 1308 Quiz 6 Solution Problem Find the rms current delivered by the 45.0 V (rms) power supply when (a) the frequency is very large (b) the frequency is very small.
200
100
45.0 V (rms) 200 F
3.00 mH
High Frequencies: Let us examine the behavior of X C in terms of the frequency. At high frequency the capacitive reactance is closed to zero, which means that the capacitor behaves like a straight wire (short circuit). Since the behavior of X L is totally the opposite, the inductor behaves like an open circuit (essentially infinite resistance ) thus at high frequencies we have as equivalent circuit:
1/2
45.0 V (rms)
200
with rms current equal to I rms =
V rms R
=
45.0 V 200
= 0.225 A
Low Frequencies At these frequencies the behaviors of X C and X L switch therefore the equivalent circuit is :
and similarly I rms =
2/2
100 45.0 V (rms)
V rms R
=
45.0 V 100
=0.45 A
200
100
45.0 V (rms) 200 F
3.00 mH
High Frequencies: Let us examine the behavior of X C in terms of the frequency. At high frequency the capacitive reactance is closed to zero, which means that the capacitor behaves like a straight wire (short circuit). Since the behavior of X L is totally the opposite, the inductor behaves like an open circuit (essentially infinite resistance ) thus at high frequencies we have as equivalent circuit:
1/2
45.0 V (rms)
200
with rms current equal to I rms =
V rms R
=
45.0 V 200
= 0.225 A
Low Frequencies At these frequencies the behaviors of X C and X L switch therefore the equivalent circuit is :
and similarly I rms =
2/2
100 45.0 V (rms)
V rms R
=
45.0 V 100
=0.45 A
