Bas Basic ic El Elec. ec. En Engr gr. . Lab Lab EC ECS S - - PowerPoint PPT Presentation

• Dr. Prapun Suksompong

prapun@siit.tu.ac.th

1

Bas Basic ic El Elec.

• ec. En

Engr gr. . Lab Lab

EC ECS S 204 04/2 /210

Office Hours: BKD 3601-7 Tuesday 9:30-10:30 Friday 14:00-16:00

Lab 5

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 RC Circuit with Voltage Step Input  Frequency Response of Series RLC Circuit  AC vs DC modes of the Oscilloscope  AC vs DC modes of the DMM  Function generator: Offset

DMM: DC vs. AC

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 VDC = Average value  VRMS = RMS value  V

AC

 

V

 

rms

V

 

 

2 2 2 AC RMS DC

V V V

DC

v t V    

   

2 2 RMS

1 V

t T t

v t v t dt T



 



   

DC

1 V

t T t

v t v t dt T



 



 

V Equal when VDC = 0.

Oscilloscope: DC vs. AC

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 Input signal:  DC mode: Show  AC mode: Show

 vAC(t) always have 0 average (theoretically.



when VDC = 0.

 

v t

   

DC

V

AC

v t v t  

   

DC

v t v t 

   

AC DC

v t v t 

Function Generator: Offset

5

   

0-offset Offset

V

• ut

v t v t  

Part A

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4Vp-p square wave

+

1k 0.1 F  

Oscilloscope Ch-1 Ch-2

Reading Capacitor Code

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Code Value 102 0.001 F 103 0.01 F 104 0.1 F 473 0.047 F 474 0.47 F

4 4 4 4 6 2 2 6 1 6 6

p 10 10 10 47 10 F 47 10 F 47 10 F 10 47 10 10 F 47 10 F =0.47 F  

     

             

 Measurement

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Three different methods:

 Measure t0.37.  Measure thalf. Then, calculate  Measure R and C. Then, calculate

 = RC.

4 V  2 2 V  1.47 V e 

half

t

0.37

t

half ln2

t  

 

0.37V 

4Vp-p square wave

+

1k 0.1 F  

Oscilloscope Ch-1 Ch-2

Part B

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R2 100  Sine-wave generator L C V Oscilloscope Ch-1 Ch-2

f f0 f2 f1 V 2 V

R

V

1 2 f LC  

Midterm Results (20%)

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5 10 15 20 25 30 10 15 20 25 30 35 40 45 50 55 Student# Scores

10 15 20 25 30 35 40 45 50 55 60 1 2 3 4 5 6 7 8