helping hand

Thread Starter

djstar

Joined Jan 26, 2008
39
could some one lease give me a helping hand with this please

17) A circuit consists of a 0.16μf capacitor connected across a 20V, 1 kHz supply. Also in parallel with the capacitor there is a 1kΩ resistor in series with a 0.18H coil.

Calculate

The current drawn from the supply
The phase angle of this current

(Use the j operator in your calculation.)
 

mik3

Joined Feb 4, 2008
4,843
could some one lease give me a helping hand with this please

17) A circuit consists of a 0.16μf capacitor connected across a 20V, 1 kHz supply. Also in parallel with the capacitor there is a 1kΩ resistor in series with a 0.18H coil.

Calculate

The current drawn from the supply
The phase angle of this current

(Use the j operator in your calculation.)
Calculate the impedance of the inductor and capacitor at 1KHz (source frequency) and then find the equivalent impedance of the circuit . Then divide the equivalent resistance of the circuit form the voltage to find the current.
 

Thread Starter

djstar

Joined Jan 26, 2008
39
thanks for the reply. ive come up with the answer

X_(c ) = 1/2πfc = X_(c ) = 1/(2×π×1000×0.00000016) = 994.71 ohms


X_l=2πfl=2 × π ×1000 ×0.18 = 1130.97 ohms


1/(1/((1130.97+1000))+ 1/994.71) = 678 Ω

20/678 = 0.029 A

sorry about the poor formula but its was done in microsoft equation wizard and hasent came out that well on this site. im still stuck with part b and with what the j operator bit means.
 

Digi Dave

Joined Apr 25, 2008
26
Z= 691.55678 ohms

I = 0.02892 amps

Phase angle 11'degrees leading because capacitor is taking more of the current than the inductor.
( tan of X / R . = 136.26/678 )
 
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