Difference between revisions of "Lab 13 TF EIM"

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DC Bipolar Transistor Curves
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Data sheet for transistors.
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[[Media:2N3904.pdf]][[Media:2N3906.pdf]]
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[[File:2N3904_PinOuts.png | 200 px]][[File:2N3906_PinOuts.png | 200 px]]
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Using 2N3904 is more srtaight forward in this lab.
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=Transistor circuit=
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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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{| border="1"  |cellpadding="20" cellspacing="0
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|-
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|Value || Description
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|-
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| || Collector-Base breakdown voltage
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|-
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| || Emitter-Base Breakdown Voltage
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|-
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| || Maximum Collector Voltage
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|-
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| || Maximum Collector Current
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|-
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| || Transistor Power rating(<math>P_{Max}</math>)
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|-
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| || DC current gain <math>h_{FE}( I_C, V_{CE})</math>
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|}
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2.) Construct the circuit below according to the type of transistor you have.
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[[File:TF_EIM_Lab13a_Circuit.png | 200 px]][[File:TF_EIM_Lab13_Circuit.png | 200 px]]
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Let <math>R_E = 100 \Omega</math>.
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<math>V_{CC}  < 5 Volts</math> variable power supply
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<math>V_{BE}=  1V</math>.
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Find  the resistors you need to have
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<math>I_B = 2 \mu A</math> , <math>5 \mu A</math> , and  <math>10 \mu A</math>
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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_{BE}}{R_B}</math>
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{| border="1"  |cellpadding="20" cellspacing="0
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|-
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|V_{CC} || V_B || V_{BB} || V_ {EC} ||  V_ E || R_E || R_B || I_E || I_B
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|-
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|mV || mV || V || mV || mV || <math>\Omega</math> || k<math>\Omega</math>|| mA|| \muA
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|-
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| || || || ||  || || || ||
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|}
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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
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{| border="1"  |cellpadding="20" cellspacing="0
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|-
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|V_{CC} || V_B || V_{BB} || V_ {EC} ||  V_ E || R_E || R_B || I_E || I_B
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|-
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|mV || mV || V || mV || mV || <math>\Omega</math> || k<math>\Omega</math>|| mA|| \muA
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|-
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| || || || ||  || || || ||
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|}
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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)
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6.) Overlay points from the transistor's data sheet on the graph in part 5.).(10 pnts)
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=Questions=
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#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 is <math>\alpha</math> for the transistor?(10 pnts)
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#The base must always be more _________(________) than the emitter for a npn (pnp)transistor to conduct I_C.(10 pnts)
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#For a transistor to conduct I_C the base-emitter  junction must be ___________ biased.(10 pnts)
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#For a transistor to conduct I_C the collector-base  junction must be ___________ biased.(10 pnts)
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=Extra credit=
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Measure the Base-Emmiter breakdown voltage. (10 pnts)
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I expect to see a graph <math>(I_{B} -vs- V_{BE} )</math> and a linear fit which is similar to the forward biased diode curves.  Compare your result to what is reported in the data sheet.
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[[Forest_Electronic_Instrumentation_and_Measurement]]
 
[[Forest_Electronic_Instrumentation_and_Measurement]]

Latest revision as of 04:03, 9 March 2011

DC Bipolar Transistor Curves

Data sheet for transistors.

Media:2N3904.pdfMedia:2N3906.pdf

2N3904 PinOuts.png2N3906 PinOuts.png


Using 2N3904 is more srtaight forward in this lab.

Transistor circuit

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


Value Description
Collector-Base breakdown voltage
Emitter-Base Breakdown Voltage
Maximum Collector Voltage
Maximum Collector Current
Transistor Power rating([math]P_{Max}[/math])
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 Lab13a Circuit.pngTF 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].

Find the resistors you need to have

[math]I_B = 2 \mu A[/math] , [math]5 \mu A[/math] , and [math]10 \mu A[/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_{BE}}{R_B}[/math]


V_{CC} V_B V_{BB} V_ {EC} V_ E R_E R_B I_E I_B
mV mV V mV mV [math]\Omega[/math] k[math]\Omega[/math] mA \muA


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

V_{CC} V_B V_{BB} V_ {EC} V_ E R_E R_B I_E I_B
mV mV V mV mV [math]\Omega[/math] k[math]\Omega[/math] mA \muA


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)

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

Extra credit

Measure the Base-Emmiter breakdown voltage. (10 pnts)


I expect to see a graph [math](I_{B} -vs- V_{BE} )[/math] and a linear fit which is similar to the forward biased diode curves. Compare your result to what is reported in the data sheet.

Forest_Electronic_Instrumentation_and_Measurement

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