Difference between revisions of "TF EIMLab13 Writeup"

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(Created page with 'The Common Emitter Amplifier =Circuit= #Construct the common emitter amplifier circuit below according to your type of emitter. #Calculate all the R and C values to use in the …')
 
 
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The Common Emitter Amplifier
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DC Bipolar Transistor Curves
  
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=Circuit=
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Data sheet for transistors.
  
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#Construct the common emitter amplifier circuit below according to your type of emitter.
+
[[Media:2N3904.pdf]][[Media:2N3906.pdf]]
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#Calculate all the R and C values to use in the circuit such that
+
 
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##<math>I_C > 0.5</math> mA DC with no input signal
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[[File:2N3904_PinOuts.png | 200 px]][[File:2N3906_PinOuts.png | 200 px]]
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##<math>V_{CE} \approx V_{CC}/2 > 2</math> V
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## <math>V_{CC} < V_{CE}(max)</math> to prevent burnout
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## <math>V_{BE} \approx 0.6 V</math>
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Using 2N3904 is more straight forward in this lab.
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##<math>I_D \approx 10 I_B < 1</math> mA  
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#Draw a load line using the <math>I_{C}</math> -vs- <math>I_{CE}</math> from the previous lab 13.  Record the value of <math>h_{FE}</math> or <math>\beta</math>.
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=Transistor circuit=
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#Set a DC operating point I^{\prime}_C so it will amplify the input pulse given to you.  Some of you will have sinusoidal pulses others will have positive or negative only pulses.
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#Measure all DC voltages in the circuit and compare with the predicted values.(10 pnts)
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'''Used to npn 2N3904 transister'''
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#Measure the voltage gain <math>A_v</math> as a function of frequency and compare to the theoretical value.(10 pnts)
+
 
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#Measure <math>R_{in}</math> and <math>R_{out}</math> at about 1 kHz and compare to the theoretical value.(10 pnts)
+
1.) Identify the type (n-p-n or p-n-p) of transistor you are using and fill in the following specifications.
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#Measure <math>A_v</math> and <math>R_{in}</math> as a function of frequency with <math>C_E</math> removed.(10 pnts)
+
 
 +
 
 +
{| border="1"  |cellpadding="20" cellspacing="0
 +
|-
 +
|Value || Description
 +
|-
 +
|40 V || Collector-Base breakdown voltage
 +
|-
 +
| 6 V|| Emitter-Base Breakdown Voltage
 +
|-
 +
| 40|| Maximum Collector Voltage
 +
|-
 +
|200 mA || Maximum Collector Current
 +
|-
 +
| 625 mW || Transistor Power rating(<math>P_{Max}</math>)
 +
|-
 +
|30 - 300 || DC current gain <math>h_{FE}( I_C, V_{CE})</math>
 +
|}
 +
 
 +
 
 +
 
 +
2.) Construct the circuit below according to the type of transistor you have.
 +
 
 +
[[File:TF_EIM_Lab13_Circuit.png | 200 px]]
 +
 
 +
 
 +
Let <math>R_E = 100 \Omega</math>.
 +
 
 +
<math>V_{CC}  < 5 Volts</math> variable power supply
 +
 
 +
<math>V_{BE}=  1V</math>.
 +
 
 +
I_B = 2<math> \mu</math> A = 1V/500 k<math> \Omega</math>
 +
: = 5<math> \mu</math> A = 1V/200 k <math>\Omega</math>
 +
: = 10 <math>\mu A</math> = 1V/100 k <math>\Omega</math>
 +
 
 +
3.) Measure the emitter current <math>I_E</math> for several values of <math>V_{CE}</math> by changing <math>V_{CC}</math> such that the base current <math>I_B = 2 \mu</math> A is constant. <math>I_B \approx \frac{V_{BB}-V_{b}}{R_B}</math>
 +
 
 +
<math>R_{B} = 500 k \Omega</math>
 +
 
 +
<math>R_{E} = 101 \Omega</math>
 +
 
 +
 
 +
{| border="1"  |cellpadding="20" cellspacing="0
 +
|-
 +
|<math>V_{BB} -V_B</math> || <math>I_B</math> || <math>V_{CC}</math> ||<math> V_ E</math> ||  <math>I_E</math>
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|-
 +
|V || <math>\mu</math> A || V || mV || mA
 +
|-
 +
|1.007 || 2||  0.0704 ||1.2 ||
 +
|-
 +
|1.05 ||2 ||0.110 ||4.9 ||
 +
|-
 +
|1.02 ||2 ||0.133 ||8.9 ||
 +
|-
 +
|1.002 ||2 ||0.162 ||15.7  ||
 +
|-
 +
| 1.002||2 ||0.184 ||21.1  ||
 +
|-
 +
|1.026 ||2 ||0.2287 ||32.3 ||
 +
|-
 +
| 1.012||2 ||0.3157 || 39.5 ||
 +
|-
 +
|1.008 ||2 ||0.484 || 40.0||
 +
|-
 +
| 1.008||2 ||1.023 || 40.3
 +
|-
 +
|1.008 ||2 ||2.167 || 40.7
 +
|-
 +
|1.008 ||2 ||2.960 || 40.8
 +
|-
 +
|1.008 ||2 ||5.00 || 41.2
 +
|-
 +
| || || ||
 +
|}
 +
 
 +
 
 +
 
 +
4.) Repeat the previous measurements for <math>I_B \approx 5 \mbox{ and } 10 \mu</math> A.  Remember to keep <math>I_CV_{CE} < P_{max}</math> so the transistor doesn't burn out
 +
 
 +
<math>R_{B} = 201.8 k \Omega</math>
 +
 
 +
{| border="1" |cellpadding="20" cellspacing="0
 +
|-
 +
|<math>V_{BB} -V_B</math> || <math>I_B</math> || <math>V_{CC}</math> ||<math> V_ E</math> ||  <math>I_E</math>
 +
|-
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|V || <math>\mu</math> A || V || mV || mA
 +
|-
 +
|1.044 || 5|| 0.094  ||7 ||
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|-
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|1.053 || 5||0.134  ||19 ||
 +
|-
 +
|1.026 || 5|| 0.167  || 32||
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|-
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|1.003 || 5|| 0.200  || 47||
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|-
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|1.003 || 5|| 0.234  ||62 ||
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|-
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|1.02 || 5|| 0.269  ||77 ||
 +
|-
 +
|1.0 || 5|| 0.289  ||83 ||
 +
|-
 +
|1.07 || 5|| 0.442  ||101 ||
 +
|-
 +
|1.02 || 5|| 0.721  ||99 ||
 +
|-
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|1.02 || 5|| 1.04  ||100 ||
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|-
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|1.02 || 5|| 1.94  ||100 ||
 +
|-
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|1.02 || 5|| 2.96 ||101 ||
 +
|-
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|1.02 || 5|| 3.72  ||102 ||
 +
|-
 +
|}
 +
 
 +
<math>R_{B} = 100 k \Omega</math>
 +
 
 +
 
 +
{| border="1"  |cellpadding="20" cellspacing="0
 +
|-
 +
|<math>V_{BB} -V_B</math> || <math>I_B</math> || <math>V_{CC}</math> ||<math> V_ E</math> ||  <math>I_E</math>
 +
|-
 +
|V || <math>\mu</math> A || V || mV || mA
 +
|-
 +
|0.942 || 10|| 0.227  ||78.1 ||
 +
|-
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|1.005 || 10|| 0.245  ||94 ||
 +
|-
 +
| 0.995|| 10|| 0.267  ||108 ||
 +
|-
 +
| 1.068|| 10||0.31  ||138 ||
 +
|-
 +
|1.005 || 10|| 0.355  ||160 ||
 +
|-
 +
| 0.996|| 10||  1.032||197 ||
 +
|-
 +
|1.002 || 10|| 0.688  ||197 ||
 +
|-
 +
|0.996|| 10|| 2.175  || 199||
 +
|-
 +
|0.994 || 10||3.283  || 200||
 +
|-
 +
| 0.992|| 10||4.66  ||202 ||
 +
|-
 +
|}
 +
 
 +
 
 +
 
 +
5.) Graph <math>I_C</math> -vs- <math>V_{CE}</math> for each value of <math>I_B</math> and <math>V_{CC}</math> above. (40 pnts)
 +
 
 +
[[File:TF_Ic-vs-VccEIM_Lab13.png]]
 +
 
 +
6.) Overlay points from the transistor's data sheet on the graph in part 5.).(10 pnts)
  
 
=Questions=
 
=Questions=
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#Why does a flat load line produce a high voltage gain and a steep load line a high current gain? (10 pnts)
+
 
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#What would be a good operating point an an <math>npn</math> common emitter amplifier used to amplify negative pulses?(10 pnts)
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1.)Compare your measured value of <math>h_{FE}</math> or <math>\beta</math> for the transistor to the spec sheet? (10 pnts)
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#What will the values of <math>V_C</math>, <math>V_E</math> , and <math>I_C</math> be if the transistor burns out resulting in infinite resistance.  Check with measurement.(10 pnts)
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:<math>\beta = \frac{I_C}{I_B} = \frac{0.5 mA}{0.002 mA} = 250</math>
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#What will the values of <math>V_C</math>, <math>V_E</math> , and <math>I_C</math> be if the transistor burns out resulting in near ZERO resistance (ie short). Check with measurement.(10 pnts)
+
2.)What is <math>\alpha</math> for the transistor?(10 pnts)
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#Predict the change in the value of <math>R_{in}</math> if <math>I_D</math> is increased from 10 <math>I_B</math> to 50 <math>I_B</math>(10 pnts)
+
 
−
#Sketch the AC equivalent circuit of the common emitter amplifier.(10 pnts)
+
3.)The base must always be more _________(________) than the emitter for a npn (pnp)transistor to conduct I_C.(10 pnts)
 +
 
 +
4.)For a transistor to conduct I_C the base-emitter  junction must be ____forward_______ biased.(10 pnts)
 +
 
 +
5.)For a transistor to conduct I_C the collector-base  junction must be ______reverse_____ biased.(10 pnts)
 +
 
 +
 
  
 
[[Forest_Electronic_Instrumentation_and_Measurement]]
 
[[Forest_Electronic_Instrumentation_and_Measurement]]

Latest revision as of 23:57, 2 April 2015

DC Bipolar Transistor Curves

Data sheet for transistors.

Media:2N3904.pdfMedia:2N3906.pdf

2N3904 PinOuts.png2N3906 PinOuts.png


Using 2N3904 is more straight forward in this lab.

Transistor circuit

Used to npn 2N3904 transister

1.) Identify the type (n-p-n or p-n-p) of transistor you are using and fill in the following specifications.


Value Description
40 V Collector-Base breakdown voltage
6 V Emitter-Base Breakdown Voltage
40 Maximum Collector Voltage
200 mA Maximum Collector Current
625 mW Transistor Power rating([math]P_{Max}[/math])
30 - 300 DC current gain [math]h_{FE}( I_C, V_{CE})[/math]


2.) Construct the circuit below according to the type of transistor you have.

TF EIM Lab13 Circuit.png


Let [math]R_E = 100 \Omega[/math].

[math]V_{CC} \lt 5 Volts[/math] variable power supply

[math]V_{BE}= 1V[/math].

I_B = 2[math] \mu[/math] A = 1V/500 k[math] \Omega[/math]

= 5[math] \mu[/math] A = 1V/200 k [math]\Omega[/math]
= 10 [math]\mu A[/math] = 1V/100 k [math]\Omega[/math]

3.) Measure the emitter current [math]I_E[/math] for several values of [math]V_{CE}[/math] by changing [math]V_{CC}[/math] such that the base current [math]I_B = 2 \mu[/math] A is constant. [math]I_B \approx \frac{V_{BB}-V_{b}}{R_B}[/math]

[math]R_{B} = 500 k \Omega[/math]

[math]R_{E} = 101 \Omega[/math]


[math]V_{BB} -V_B[/math] [math]I_B[/math] [math]V_{CC}[/math] [math] V_ E[/math] [math]I_E[/math]
V [math]\mu[/math] A V mV mA
1.007 2 0.0704 1.2
1.05 2 0.110 4.9
1.02 2 0.133 8.9
1.002 2 0.162 15.7
1.002 2 0.184 21.1
1.026 2 0.2287 32.3
1.012 2 0.3157 39.5
1.008 2 0.484 40.0
1.008 2 1.023 40.3
1.008 2 2.167 40.7
1.008 2 2.960 40.8
1.008 2 5.00 41.2


4.) Repeat the previous measurements for [math]I_B \approx 5 \mbox{ and } 10 \mu[/math] A. Remember to keep [math]I_CV_{CE} \lt P_{max}[/math] so the transistor doesn't burn out

[math]R_{B} = 201.8 k \Omega[/math]

[math]V_{BB} -V_B[/math] [math]I_B[/math] [math]V_{CC}[/math] [math] V_ E[/math] [math]I_E[/math]
V [math]\mu[/math] A V mV mA
1.044 5 0.094 7
1.053 5 0.134 19
1.026 5 0.167 32
1.003 5 0.200 47
1.003 5 0.234 62
1.02 5 0.269 77
1.0 5 0.289 83
1.07 5 0.442 101
1.02 5 0.721 99
1.02 5 1.04 100
1.02 5 1.94 100
1.02 5 2.96 101
1.02 5 3.72 102

[math]R_{B} = 100 k \Omega[/math]


[math]V_{BB} -V_B[/math] [math]I_B[/math] [math]V_{CC}[/math] [math] V_ E[/math] [math]I_E[/math]
V [math]\mu[/math] A V mV mA
0.942 10 0.227 78.1
1.005 10 0.245 94
0.995 10 0.267 108
1.068 10 0.31 138
1.005 10 0.355 160
0.996 10 1.032 197
1.002 10 0.688 197
0.996 10 2.175 199
0.994 10 3.283 200
0.992 10 4.66 202


5.) Graph [math]I_C[/math] -vs- [math]V_{CE}[/math] for each value of [math]I_B[/math] and [math]V_{CC}[/math] above. (40 pnts)

TF Ic-vs-VccEIM Lab13.png

6.) Overlay points from the transistor's data sheet on the graph in part 5.).(10 pnts)

Questions

1.)Compare your measured value of [math]h_{FE}[/math] or [math]\beta[/math] for the transistor to the spec sheet? (10 pnts)

[math]\beta = \frac{I_C}{I_B} = \frac{0.5 mA}{0.002 mA} = 250[/math]

2.)What is [math]\alpha[/math] for the transistor?(10 pnts)

3.)The base must always be more _________(________) than the emitter for a npn (pnp)transistor to conduct I_C.(10 pnts)

4.)For a transistor to conduct I_C the base-emitter junction must be ____forward_______ biased.(10 pnts)

5.)For a transistor to conduct I_C the collector-base junction must be ______reverse_____ biased.(10 pnts)


Forest_Electronic_Instrumentation_and_Measurement

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