A Beta-Stabilized, C-E BJT Circuit (Pt2): Part Select, Rev Engineer, Bench Results (066c2)

In the last video I covered the circuit analysis and design of the beta-stabilized version of the bipolar junction transistor circuit that I had promised in my videos on the analysis and design of the common-emitter and common-collector BJT circuits. I had calculated all of the values associated with that design ... R1, R2, Rc and Re.
In this video I will select parts, reverse engineer the circuit given the parts I do find, and implement it on the bench to see how we did.
I am making the assumption that you are coming to this video having, first, watched part 1 where I did the initial analysis and design. I will be using equations arrived at through that process here without repeating their derivation. Nonetheless, I will be using Kirchhoff's Voltage Law and Thevenin's Theorem to accomplish the task or reverse engineering this circuit. If you are not familiar with these, I've provided links to my videos on these subjects, below.
Once I have completed the reverse engineering process and we know what to expect on the bench, I will put this together on the bench to see how our real performance matches up with theory.
While on the bench, I will swap out transistors to demonstrate the effects of the beta variations from transistor-to-transistor will have on the performance of the circuit. Further, I will compare its performance to a basic common-emitter circuit designed around the same operating parameters.
I have created a "go-along-with-the-video" sheet which steps through the whole process. You will also find formulas for things like input impedance, output impedance and voltage gain (with and without the emitter resistor bypass capacitor) in this sheet. The link to this sheet is below.
I've provided links to all of the videos in this series below.
=============== LINKS =================
LINK to the promised formula sheet:
drive.google.c...
=== VIDEO LINKS ===
Kirchhoff's Voltage Law
• Kirchhoff's Voltage La...
Thevenin's Theorem
• Thevenin's Theorem: Ba...
Links to all of the videos in this series are below the time markers.
=======================================
Time Markers for Your Convenience
----------------------------
02:17 Component Selection
04:15 Reverse Engineering
04:30 Calculate Vth and Rth
06:04 Calculating the Base current
10:14 The Emitter-Collector Circuit
10:41 Calculating the V(Re)
11:02 Calculating the Emitter current
12:34 Calculating V(Rc)
12:54 Calculating the Collector current
14:18 Calculate the Collector voltage
14:19 Calculate Vce
16:28 The Bench Results
19:00 Final Comments and Toodle-Oots
-----------------------------
==== This video Series ====
Video#1: Introduction to the Junction Diode (How PN junctions work)
• Introducing PN Junctio...
Video#2: Introduction to the Bipolar Junction Transistor (BJT)
• Introducing Bipolar Ju...
Video#3: Basic Bipolar Junction Transistor (BJT) Metrics for the Experimenter
• Basic Bipolar Junction...
Video #4 Basic Bipolar Junction Transistor Analysis: The Model
• Basic Bipolar Junction...
Video #5 Basic Bipolar Junction Transistor Analysis: The Common-Emitter Circuit
• Basic Bipolar Junction...
Video #6 Basic Bipolar Junction Transistor Analysis: The Common-Collector Circuit
• Basic Bipolar Junction...
Video #7 Basic Bipolar Junction Transistor Analysis: The Common-Base Circuit
• Basic Bipolar Junction...
Video #8 A Beta Stabilized Common-Emitter BJT Circuit: Analysis & Design
• A Beta-Stabilized, Com...
Video #9 A Beta Stabilized Common-Emitter BJT Circuit: Part Selection, Reverse Engineering and Bench Results
• A Beta-Stabilized, C-E...

[@user-em7lp1sb4k]

There's a lot here to unpack thanks for all the hard work for putting this subject together. Also the work sheets are really helpful as well. Really appreciate the hard work Ralph.

[@eie_for_you]

I have to agree. There is a LOT in there. I am so glad that you are finding these videos and the sheets that go with them helpful to you. They are blast to do. I print out a copy of the sheet for a design notebook I keep for my own reference as well. 🙂

[@Martock1017]

Thanks for a thought-provoking analysis of this basic circuit. I did manage to remember Thevenin and Kirchoff's Laws which I first encountered 60 years ago at Technical College. An interesting exercise for people to try would be replacing your resistors with the nearest preferred values, either from the 12 values per decade (E12) or 24 values-per-decade (E24) series and compare the results with the basic C-E circuit.

[@eie_for_you]

You are very welcome! I always found the whole Thevenin thing weird. Kirchhoff's stuff makes sense, but Thevenin ...? You are right, once we get it "all figured out", we still have to get parts we can buy. Then comes the fun ... accommodating part tolerances! 🙂

[@Martock1017]

Now you've jogged my memory, there was also the Norton equivalent constant-current generator, which was the one I found more difficult to understand. @@eie_for_you

[@haraldlonn898]

You could also use a resistor base collector to stabilize the transistor. It was the way I knew before I learned how in school. Thanks for great videos.

[@eie_for_you]

Now that is interesting! I do not remember seeing that. Negative feedback. I'll have to do a simulation with that while I am on the road today. 🙂

[@randyanders]

I'm already looking forward to your next excellent endeavor(s)

[@eie_for_you]

As you have already seen ... it is there. Thanks! This is so much fun! 🙂

[@ornithopterindia]

👍Thank you sir.

[@eie_for_you]

You are welcome! 🙂

[@davidluther3955]

WHY DID YOU NOT HAVE A PRESENTATION FOR THE AC WITH THE INPUT AND OUTPUT IIMPEDANCES AND GAIN FOR THESE TRANSISTOR CONFIGURATIONS?ONE TRANSISTOR CONFIGURATION THAT WOULD BE INTERESTING TO LEARN ABOUT IS COLLECTOR FEEDBACK.

[@eie_for_you]

This video is the *second* video in a two video pair on this subject. Video 1 (kzbin.info/www/bejne/p16yaXRrh5aDjJo) was on analysis and design using the intended overall gain and input and output impedances to determine the ideal values required to meet the design criterion. This second video shows how to go about taking the actual resistance values that you are implementing the design with and determining what the circuit should actually act like based on those values. This, then, is followed by the bench experiment were we see how close we actually came to a real-world circuit in our calculations. Anything beyond these goals is out of the intended scope of either of these videos. 🙂

[@davidluther3955]

WHERE DID YOU GET THOSE RESISTOR NUMBER VALUES FROM YOUR JUNCK BOX?THEY DO NOT SEEM LIKE STANDARD VALUES.

[@eie_for_you]

Many of my resistors are 1% resistors. Those folks who are used to the standard resistors values of the 5% and 10% variety (e.g. 27K, 33K, etc), these look pretty odd (and they are! Like 4.99K!?). Here is a great chart for you ... dazyweblabs.blogspot.com/2013/09/standard-resistor-value-chart.html 🙂

[@davidluther3955]

​@@eie_for_youTHANK YOU!

[@eie_for_you]

@@davidluther3955 You are welcome! 🙂