lab3-1 - Boise State University Department of Electrical...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Boise State University Department of Electrical and Computer Engineering ECE 212L Circuit Analysis and Design Lab Experiment #3: Impedance Measurements 1 Objectives The objectives of this laboratory experiment are: to use phase and amplitude measurements in the determination of unknown series and parallel impedance connections. 2 Theory In this experiment, we will explore several ways of measuring the impedance of a black box whose impedance is unknown. There are two types of black boxes as shown in Table 1 below. Table 1: Types of Black Boxes Type Impedance Description SRL Series RL Circuit PRC Parallel RC Circuit In addition, type SRL can consist of a nonideal inductor having a small series resistance and type PRC can consist of a single, almost ideal, capacitor with no shunt resistor in parallel with it. 2.0.1 Series RL Circuit- V 1 ~ +- V 2 ~ (a) (b) R s R s R c R c j L L s s + +- v (t) 1 +- v (t) 2 Figure 1: Series RL Impedance Determination Consider the series RL circuit shown in Figure 1 where R s and L s are unknown elements to be determined. This unknown series impedance is placed in series with a calibrating series resistor with known value R c . Assume that the sinusoidal input and voltages, v 1 ( t ) and v 2 ( t ), respectively, v 1 ( t ) = 2 V 1 cos( t ) v 2 ( t ) = 2 V 2 cos( t ) = 2 AV 1 cos( t ) (1) 1 are observed with a dual-trace oscilloscope. The transfer function between the output phasor voltage V 2 and the input voltage phasor V 1 is obtained as V 2 V 1 = R c R c + R s + jL s = R c ( R c + R s ) 2 + ( L s ) 2 tan 1 L s R c + R s (2) On the other hand, V 2 V 1 = A (3) Therefore, the amplitude ratio of the two waveforms can be determined from the rms or peak-to- peak voltage magnitudes as A = | V 2 | | V...
View Full Document

Page1 / 6

lab3-1 - Boise State University Department of Electrical...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online