DE LA SALLE UNIVERSITY – DASMARINAS

COLLEGE OF ENGINEERING, ARCHITECTURE AND TECHNOLOGY

EXPERIMENT NO. 5

“IMPEDANCE OF A PARALLEL RL, RC, AND RLC CIRCUIT”

SCORE:

CANIEDO, JOHN CARLO T. SUBMITTED TO:

DATE PERFORMED: JANUARY 2015 ENGR. JUANCHO O. NATIVIDAD

DATE SUBMITTED: JANUARY 2015

I. DISCUSSIONS AND ANALYSIS OF RESULTS

In this experiment we are about to determine the relationship of the resistor,

capacitor and inductor configured in parallel. As the elements are being connected

parallel in each branches in the circuit, the impedance of the parallel branches combine

in the same way that parallel resistor combine.

In Parallel RL, when the resistors and inductors are mixed together in parallel

circuits (just in series circuits), the total impedance will have a phase angle somewhere

between 0 to +90 electrical degrees. The circuit current will have a phase angle

somewhere between 0 to -90 electrical degrees.

In Parallel RC, when resistors and capacitors are mixed together in parallel, the

total impedance will have a phase angle between 0 to -90 electrical degrees and the

circuits current will have a phase angle between 0 to +90.

In parallel AC circuits it is more convenient to use admittance, symbol ( Y ) to

solve complex branch impedance’s especially when two or more parallel branch

impedance’s are involved (helps with the math’s). The total admittance of the circuit can

simply be found by the addition of the parallel admittances. Then the total

impedance, ZT of the circuit will therefore be 1/YT Siemens.

Reference:

1001 Solved Problems in Electrical Engineering by Romeo A. Rojas

Self-Sufficient Guide to ECE Electronics Engineering by Jason M. Ampoloquio,

PECE

II. CONCLUSION

After the experiment we are able to further understand not only the series

configuration of R-L-C circuit but the parallel in additional. We are able to determine the

behavior of each element and their phase relationship with each other in the circuit

using the oscillator.

Because inductors and capacitors act differently to different inputs, there is some

potential for the circuit response to approach infinity when subjected to certain types

and amplitudes of inputs. When the output of a circuit approaches infinity, I therefore

conclude that the circuit is said to be unstable. Thus, an unstable circuits can actually

be dangerous, as unstable elements overheat, and potentially rupture.

I concluded that the circuit is considered to be stable when a "well-behaved"

input produces a "well-behaved" output response. I use the term "Well-Behaved"

differently for each application, but generally, we mean "Well-Behaved" to mean a finite

and controllable quantity.

We have compared the theoretical results with measured results, and I

concluded that we may have some uncertainty with the measured values, but we are

able to carefully lessen error possible when we are about to compare the measured in

the computed values.

III. QUESTIONS AND PROBLEMS