Difference between revisions of "Lab 13 RS"

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|Value || Description
 
|Value || Description
 
|-
 
|-
| || Collector-Base breakdown voltage
+
| <math>V_{(BR)CEO} = 40\ V</math> || Collector-Base breakdown voltage
 
|-
 
|-
| || Emitter-Base Breakdown Voltage
+
| <math>V_{(BR)EBO} = 6\ V</math> || Emitter-Base Breakdown Voltage
 
|-
 
|-
| || Maximum Collector Voltage
+
| <math>V_{(BR)CEO} = 40\ V</math> || Maximum Collector-Emitter Voltage
 
|-
 
|-
| || Maximum Collector Current
+
| <math>V_{(BR)CBO} = 60\ V</math> || Maximum Collector-Emitter Voltage
 
|-
 
|-
| || Transistor Power rating(<math>P_{Max}</math>)
+
| <math>I_C = 200\ mA</math> || Maximum Collector Current - Continuous
 
|-
 
|-
| || DC current gain <math>h_{FE}( I_C, V_{CE})</math>
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| <math>625\ mW</math> || Transistor Power rating(<math>P_{Max}</math>)
 +
|-
 +
| <math>h_{FE} = </math> || DC current gain <math>h_{FE}( I_C, V_{CE})</math>
 +
|-
 +
| <math>h_{FE} = 40</math> <math>h_{FE} = 70</math> <math>h_{FE} = 100</math>||  <math>I_C = 0.1\ mA</math>, <math>V_{CE} = 1.0\ V</math>
 
|}
 
|}
  

Revision as of 05:58, 10 March 2011

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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
[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]625\ mW[/math] Transistor Power rating([math]P_{Max}[/math])
[math]h_{FE} = [/math] DC current gain [math]h_{FE}( I_C, V_{CE})[/math]
[math]h_{FE} = 40[/math] [math]h_{FE} = 70[/math] [math]h_{FE} = 100[/math] [math]I_C = 0.1\ mA[/math], [math]V_{CE} = 1.0\ V[/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.



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