Difference between revisions of "Lab 13 RS"

From New IAC Wiki
Jump to navigation Jump to search
Line 14: Line 14:
  
 
=Transistor circuit=
 
=Transistor circuit=
1.) Identify the type (n-p-n or p-n-p) of transistor you are using and fill in the following specifications.
+
== Identify the type (n-p-n or p-n-p) of transistor you are using and fill in the following specifications. ==
  
  
Line 50: Line 50:
  
  
2.) Construct the circuit below according to the type of transistor you have.
+
== Construct the circuit below according to the type of transistor you have. ==
  
 
[[File:TF_EIM_Lab13a_Circuit.png | 300 px]][[File:TF_EIM_Lab13_Circuit.png | 300 px]]
 
[[File:TF_EIM_Lab13a_Circuit.png | 300 px]][[File:TF_EIM_Lab13_Circuit.png | 300 px]]
Line 74: Line 74:
  
  
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>
+
== 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> ==
  
  
  
{| border="1"  |cellpadding="20" cellspacing="0
+
{| border="1" cellspacing="0"  cellpadding="10" style="text-align: center"
|-
+
!scope="row" |<math>V_{CC}</math>
|V_{CC} || V_B || V_{BB} || V_ {EC} |V_ E || R_E || R_B || I_E || I_B
+
!scope="row" |<math>V_{B}</math>
|-
+
!scope="row" |<math>V_{BB}</math>
 +
!scope="row" |<math>V_{EC}</math>
 +
!scope="row" |<math>V_{E}</math>
 +
!scope="row" |<math>R_{E}</math>
 +
!scope="row" |<math>R_{B}</math>
 +
!scope="row" |<math>I_{E}</math>
 +
!scope="row" |<math>I_{B}</math>
 +
|-  
 
|mV || mV || V || mV || mV || <math>\Omega</math> || k<math>\Omega</math>|| mA|| \muA
 
|mV || mV || V || mV || mV || <math>\Omega</math> || k<math>\Omega</math>|| mA|| \muA
 
|-
 
|-
Line 90: Line 97:
  
  
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
+
== 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
  
{| border="1"  |cellpadding="20" cellspacing="0  
+
{| border="1"  |cellpadding="20" cellspacing="0 ==
 
|-
 
|-
 
|V_{CC} || V_B || V_{BB} || V_ {EC} ||  V_ E || R_E || R_B || I_E || I_B
 
|V_{CC} || V_B || V_{BB} || V_ {EC} ||  V_ E || R_E || R_B || I_E || I_B

Revision as of 04:43, 11 March 2011

Go Back to All Lab Reports


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

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

I am going to use n-p-n transistor 2N3904. Below are some specifications from data shits for this type of transistor:

Value Description
[math]V_{(BR)CEO} = 40\ V[/math] Collector-Base breakdown voltage
[math]V_{(BR)EBO} = 6\ V[/math] Emitter-Base Breakdown Voltage
[math]V_{(BR)CEO} = 40\ V[/math] Maximum Collector-Emitter Voltage
[math]V_{(BR)CBO} = 60\ V[/math] Maximum Collector-Emitter Voltage
[math]I_C = 200\ mA[/math] Maximum Collector Current - Continuous
[math]P = 625\ mW[/math] Transistor Power rating([math]P_{Max}[/math])
[math]h_{FE}\ min \ [/math] [math]h_{FE}\ max \ [/math] [math]I_C[/math], [math]V_{CE}[/math]
40 300 [math]I_C=0.1\ mA[/math], [math]V_{CE}=1.0\ V[/math]
70 300 [math]I_C=1\ mA[/math], [math]V_{CE}=1.0\ V[/math]
100 300 [math]I_C=10\ mA[/math], [math]V_{CE}=1.0\ V[/math]
60 300 [math]I_C=50\ mA[/math], [math]V_{CE}=1.0\ V[/math]
30 300 [math]I_C=100\ mA[/math], [math]V_{CE}=1.0\ V[/math]


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}= 1\ V[/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]

By measurements I was able to find that [math]V_{BE}= 0.6\ V[/math]. So I am going to use this value. Also let picks up [math]V_{BB}= 1.6\ V[/math]. So my current [math]I_B = \frac{V_{BB} - V_{BE}}{R_B} = \frac{(1.6 - 0.6)\ V}{R_B} = \frac{1.0\ V}{R_B}[/math].

Now to get [math]I_B = 2\ \mu A[/math] I need to use [math]R_B = \frac{1.0\ V}{2\ \mu A} = 500\ k\Omega[/math]
    To get [math]I_B = 5\ \mu A[/math] I need to use [math]R_B = \frac{1.0\ V}{5\ \mu A} = 200\ k\Omega[/math]
    To get [math]I_B = 10\ \mu A[/math] I need to use [math]R_B = \frac{1.0\ V}{10\ \mu A} = 100\ k\Omega[/math]



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]

[math]V_{CC}[/math] [math]V_{B}[/math] [math]V_{BB}[/math] [math]V_{EC}[/math] [math]V_{E}[/math] [math]R_{E}[/math] [math]R_{B}[/math] [math]I_{E}[/math] [math]I_{B}[/math]
mV mV V mV mV [math]\Omega[/math] k[math]\Omega[/math] mA \muA


== 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.



Go Back to All Lab Reports Forest_Electronic_Instrumentation_and_Measurement