Week #8: (10/24-28) Transistor Biasing

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rjagodowski
Posts: 2371
Joined: Fri Sep 04, 2015 6:59 pm

Week #8: (10/24-28) Transistor Biasing

Post by rjagodowski »

This week's lab will be Experiment #5 handouts on Transistor Bias Circuits. A copy will be provided for you during Tuesday's class on 10/25. A pdf of this lab can be found in the Registered Users Only area here. You must be registered and logged in to view content in this area.)

You may find this link to Transistor Biasing from Electronics-Tutorials.ws handy.

When you complete this exercise, create a progress report post as a Reply to this Topic.

You will perform the calculations, build and test the four circuits in Part 1 of the lab sheets, then build them in EWB or Circuit Maker and compare the results to your measurements and calculations. (EWB is currently not installed on our computers so you DO NOT have to do the EWB aspects of this lab at this time. Stay tuned.) The circuits in Part 2 you will build only in EWB or Circuit Maker.

Part 1: Build & verify all 4 circuits. Suggestion: Use your multi-meter to check each transistor BEFORE putting it in the circuit. Here is a pdf of the procedure:
Transistor DMM Check.pdf
(71.08 KiB) Downloaded 206 times
You will make the measurements for each of 3 transistors for each circuit. This will help demonstrate the stability of the Q-point with respect to transistor variations. Sample EWB files are included below for your convenience. You can change the value of beta used in the WEB IDEAL transistor model by right-clicking on the transistor, select properties and then adjust the Forward Current Gain parameter to the value of beta.

Here are the formulas required for each circuit:

Fig. 5-1:
VRB=VCC-0.7V
IB=(VCC-0.7V)/RB
IC=(beta)*IB (assume beta around 150-200)
VRC=IC * RC
VC=12V-VRC
VCE=VC-VE=VC-0=VC


Fig. 5-2:
IB=(VCC-0.7)/(RB+beta*RE)
VRB=IB*RB
IC=beta*IB
VRC=IC*RC
VC=VCC-VRC
VCE=VC-VE=VC-VRE where VRE=IC*RE

Fig. 5-3:
VB=VCC(R2/(R1+R2))
VE=VB-0.7
IE=IC=(VE-0)/RE
VRC=IC*RC
VC=VCC-VRC
VCE=VC-VE

Fig. 5-4:
VB=0.7
IE=IC= (VCC-VBE)/(RB/beta+RC)=(VCC-0.7)/(RB/beta+RC)
VRC=IC*RC
VC=VCC-VRC



Part 2: Do not build these circuits. (EWB should be available within the next few weeks.) Verify these circuits using Electronics Workbench only. You have to create these circuits on your own. Be sure to save the EWB file for each circuit you create.


Here's a picture of the pinouts for common small-signal transistors:
Transistor Pinouts.jpg
Transistor Pinouts.jpg (150.78 KiB) Viewed 5156 times
rawhite0001

Re: Week #8: (10/24-28) Transistor Biasing

Post by rawhite0001 »

I have completed the lab up to the assigned point.
jcpetlock0001

Re: Week #8: (10/24-28) Transistor Biasing

Post by jcpetlock0001 »

I have completed the lab up to part 2
arbeben0001

Re: Week #8: (10/24-28) Transistor Biasing

Post by arbeben0001 »

I have completed!
vshovgan0001
Posts: 43
Joined: Fri Sep 11, 2015 9:28 am

Re: Week #8: (10/24-28) Transistor Biasing

Post by vshovgan0001 »

lab completed
dmherd0001
Posts: 25
Joined: Tue Sep 13, 2016 11:44 am

Re: Week #8: (10/24-28) Transistor Biasing

Post by dmherd0001 »

lab done
mfdesjardins0001

Re: Week #8: (10/24-28) Transistor Biasing

Post by mfdesjardins0001 »

I have completed this lab. Michael Desjardins
jariopelle

Re: Week #8: (10/24-28) Transistor Biasing

Post by jariopelle »

Lab complete
nacolon

Re: Week #8: (10/24-28) Transistor Biasing

Post by nacolon »

Lab complete
arguilbert0001

Re: Week #8: (10/24-28) Transistor Biasing

Post by arguilbert0001 »

Lab Completed!
jplynch0001

Re: Week #8: (10/24-28) Transistor Biasing

Post by jplynch0001 »

Lab Complete
bemmonds
Posts: 38
Joined: Sun Sep 11, 2016 11:50 am

Re: Week #8: (10/24-28) Transistor Biasing

Post by bemmonds »

Lab complete.
Brad E.
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