# Complex voltage in RL circuit

Discussion in 'Homework Help' started by Tera-Scale, Jan 4, 2011.

1. ### Tera-Scale Thread Starter Active Member

Jan 1, 2011
164
5
Hi, A complex voltage :
v = 100sin(377t) + 50sin(754t) + 5sin(1508t) V is applied to the LR circuit.
Z1 = 25Ω Z2: R = 13.3Ω Xl = 31.2Ω L = 85.3mH

These I managed to work out:

Determine rms of complex voltage waveform.
i)Obtain an expression for the complex current i
i=2.64sin(377t-1.01c)+0.74sin(754t-1.27c)+0.037sin(1508t-1.264c)
ii) Deduce value of true power that flows in circuit = 79.4V
iii) determine overall power factor. = 0.93

On this part I would like some advise on what to include, even some points and i will go into more detail. (Please find attached schematic and graph)
I remember my teacher mentioning on commenting on the power factor..

iv) Comment on the complex waveforms and the results obtained:

Present and communicate your results and findings in a logical way. Producing appropriate plots to show how the complex voltage and current in the circuit vary with time over one complete cycle will help to communicate your results obtained.

2. ### Georacer Moderator

Nov 25, 2009
5,142
1,266
You could comment on how the various frequencies pass through the LR filter and talk about the different power factors for each frequency and how they combine to give the overall power factor.

Just a thought.