Week #10: (11/9-13) Transistor Biasing, dB & Gain

Post Reply
rjagodowski
Posts: 2368
Joined: Fri Sep 04, 2015 6:59 pm

Week #10: (11/9-13) Transistor Biasing, dB & Gain

Post by rjagodowski »

This week we will wrap up our discussion of biasing bipolar junction transistor amplifiers. We'll be doing the A.C. analysis of these circuits soon. This week we'll review what we've learned for D.C. biasing, learn about amplifier classifications and develop some experience with decibels and gain. In addition, we'll discuss the concept of signal distortion.

Our next transistor lab is found here.

Some summary links:

Common Emitter Voltage Divider Bias Summary, pay special attention to the graph showing the sinusoidal variations of iB, iC 7 VCE.

Here's a good review & practice of Voltage Divider biased transistors from Wisc-online.com . Calculating D.C. Values for a Resistor Bias Class A amplifier, from Wisc-Online.


We'll discuss Gain calculations (below) then continue with the following:

Class A, Class B and Class AB amplifiers, Cross-over Distortion.


Amplifier Distortion

Here's a link that will let you hear the effects of distortion common waveshapes. http://www.falstad.com/mathphysics.html. Scroll down to the "Signal Processing" simulations, then open the "Fourier Series Applet". These simulation do require a Java-enabled web browser. Set the signal to a sinusoid, set the frequency & volume to a comfortable combination, click the "Sound Option" and listen as you "Clip" the wave. You can also manually distort the wave using your mouse. Note that ANY change (distortion) to the basic sine wave results in higher frequencies being added to the signal. These frequencies are called "Harmonics". An ideal amplifier will amplify the input signal with the least addition of harmonics. Often times you will see a "Total Harmonic Distortion" specification in an amplifier spec sheet. This relates the total amount of distortion which may be added to a signal by that amplifier.

Efficiency, Gain and dBs from AllAboutCircuits.com and Amplifier Gains from Electronic-Tutorials.ws (scroll down a bit).

Decibels, Gain, Power & Voltage from Wisc-online.

A handy summary of dB Conversions.

Amplifier Summary from Electronics-Tutorials.ws.


Wikipedia on Differential Amplifiers, Common & Differential Mode Operation.


Here are some practice problems on Gain Calculations. We'll eventually cover this entire sheet, but for now look at problems 1, 2 & 3.
Attachments
Gain Calculation Problems v15.1.pdf
(65.29 KiB) Downloaded 170 times
ajjorge

Re: Week #10: (11/9-13) Transistor Biasing, dB & Gain

Post by ajjorge »

Lab complete
Attachments
wk10_1solidstate.png
wk10_1solidstate.png (28.51 KiB) Viewed 2431 times
wk10_1solidstate2.png
wk10_1solidstate2.png (31.06 KiB) Viewed 2431 times
ljbaker0001

Re: Week #10: (11/9-13) Transistor Biasing, dB & Gain

Post by ljbaker0001 »

Lab completed
Attachments
wk10_1solidstate1.png
wk10_1solidstate1.png (28.57 KiB) Viewed 2430 times
wk10_1solidstate2.png
wk10_1solidstate2.png (31.04 KiB) Viewed 2430 times
Post Reply

Return to “Lecture”