Difference between revisions of "Lab 6 RS"

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==Adjust the pulse generator to output square pulses which at <math>\tau \approx</math> RC/10.==
 
==Adjust the pulse generator to output square pulses which at <math>\tau \approx</math> RC/10.==
  
[[File:Lab6 f2.png | 600 px]]
+
[[File:Lab6 f2.png | 400 px]]
  
 
==Measure<math> V_{in}</math> and <math>V_{out}</math>.  Sketch a picture comparing<math> V_{out}</math> and <math>V_{in}</math>. ( 5 pnts.)==
 
==Measure<math> V_{in}</math> and <math>V_{out}</math>.  Sketch a picture comparing<math> V_{out}</math> and <math>V_{in}</math>. ( 5 pnts.)==
  
 
==Change the pulse width such that <math>\tau=</math>RC==
 
==Change the pulse width such that <math>\tau=</math>RC==
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 +
[[File:Lab6 f3.png | 400 px]]
  
 
==Measure<math> V_{in}</math> and <math>V_{out}</math>.Sketch a picture comparing<math> V_{out}</math> and <math>V_{in}</math>.( 5 pnts.)==
 
==Measure<math> V_{in}</math> and <math>V_{out}</math>.Sketch a picture comparing<math> V_{out}</math> and <math>V_{in}</math>.( 5 pnts.)==
  
 
==Change the pulse width such that <math>  \tau</math>=10 RC==
 
==Change the pulse width such that <math>  \tau</math>=10 RC==
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 +
[[File:Lab6 f3.png | 400 px]]
  
 
==Measure <math>V_{in}</math> and <math>V_{out}</math>.Sketch a picture comparing<math> V_{out}</math> and <math>V_{in}</math>.( 5 pnts.)==
 
==Measure <math>V_{in}</math> and <math>V_{out}</math>.Sketch a picture comparing<math> V_{out}</math> and <math>V_{in}</math>.( 5 pnts.)==

Revision as of 05:52, 10 February 2011

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Lab 6 Pulses and RC Filters

Differentiator

Construct the circuit below selecting an RC combination such that RC [math]\lt 10^{-4} [/math] s

TF EIM Lab6b.png


Lab6 formula1 m1.png


Adjust the pulse generator to output square pulses which at [math]\tau \approx[/math] RC/10.

Lab6 f2.png

Measure[math] V_{in}[/math] and [math]V_{out}[/math]. Sketch a picture comparing[math] V_{out}[/math] and [math]V_{in}[/math]. ( 5 pnts.)

Change the pulse width such that [math]\tau=[/math]RC

Lab6 f3.png

Measure[math] V_{in}[/math] and [math]V_{out}[/math].Sketch a picture comparing[math] V_{out}[/math] and [math]V_{in}[/math].( 5 pnts.)

Change the pulse width such that [math] \tau[/math]=10 RC

Lab6 f3.png

Measure [math]V_{in}[/math] and [math]V_{out}[/math].Sketch a picture comparing[math] V_{out}[/math] and [math]V_{in}[/math].( 5 pnts.)

Questions

What happens if the amplitude of [math]V_{in}[/math] is doubled.( 5 pnts.)

What happens if R is doubled and C is halved?( 5 pnts.)

Integrator

Now repeat the above experiment with the resistor and capacitor swapped to form the low pass circuit below.

TF EIM PulsedRCLowpass.png

Pulse Sharpener

The goal of this section is to demonstrate how well the circuit below can sharpen an input pulse

TF EIM Lab6a.png

1.) The first step is to create an input pulse which is rounded, similar to the output of the integrator circuit when RC = 10 [math]\tau[/math]. You can do this using a capacitor shorted across the output of the pulse generator. This will essential be coupled to the input impedance of the pulse generator and form a low pass circuit.

As a result the input voltage is given as

[math]V_{in} = V_0 \left ( 1 - e^{-t/\tau}\right )[/math]

where

[math]\tau=R_{out} C_{out}[/math]
[math]R_{out}[/math] = impedance of the function generator at output which produces V_{in}
[math]C_{out}[/math] = capacitor shorting the function generator output to ground (not shown in the above picture)

2.) The output should be given by

[math]V_{out} = V_0^{\prime} \left ( 1 - e^{-t/\tau^{\prime}}\right )[/math]

where

[math]\tau^{\prime} =\left ( \frac{R_1 R}{R_1+ R}\right )C_1[/math]

3.) Make measurements of the rise time [math]\tau[/math] and [math]\tau^{\prime}[/math]. The rise time is defined as the time it take the pulse to go from 10% of its max value to 90% of its max value.( 5 pnts.)

4.) Compare the measurement of [math]\tau^{\prime}[/math] to what you expected based on your measured values of [math]C_1[/math], [math]R_1[/math] and[math] R[/math].( 15 pnts.)

Questions

1.) Qualitatify, why is [math]\tau^{\prime} \lt \tau[/math]?( 10 pnts.)

2.) How is [math]V_{out}[/math] worse than [math]V_{in}[/math]( 10 pnts.)



Forest_Electronic_Instrumentation_and_Measurement

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