CASCODE Amplifier (Pt 3): Designing in a Fixed Gain (066g3)

BJT Circuit Analysis: The CASCODE Amplifier (Pt 3) - Designed in Gain (066g3)
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This is the third video in this series on the CASCODE Amplifier.
In the first video, I explained the WHY behind the CASCODE configuration and the HOW it works behind its operation. Here is a LINK to that video if you missed it:
• BJT Circuit Analysis: ...
In the last video, I showed you how to design one. Here is a LINK to that video if you missed that one:
• BJT Circuit Analysis: ...
In this video I will be showing you how to design in a specific gain to the amplifier. I will show you three ways to accomplish this. I will also show how the gain limited versions improve the upper end bandwidth of the amplifier.
As a kind of extra credit portion, I am going to show the effects of the source impedance on the performance of the amplifier.
=== LINKS for You ===
LINK to the Early Voltage video:
• What is Early Voltage?...
LINK to the "Go-Along-With-The-Video" formula sheet:
drive.google.c...
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Time Markers for Your Convenience
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00:05 Introductions
02:12 A Few Simple Definitions
04:20 WAY #1: Set Rc
06:58 WAY #2: Feedback
09:17 WAY #3: Split Emitter Resistor
13:22 The Effects of Source Impedance
15:41 Parting Comments and Toodle-Oots

[@W1RMD]

FINALLY...The ham shack! Thanks for sharing and 73!- W1RMD

[@eie_for_you]

🙂 You are very welcome! 🙂

[@U812-k7j]

Ralph's ham shack😎
I was expecting all kinds of homebrew gear what's up with that Ralph🤗
Thanks again for another great video I always learn something.

[@eie_for_you]

I am so glad that you benefited from the video! 🙂You are very welcome!
Well, the homebrew stuff is "hiding" in the background. For instance, there is a small box on top of the power supply with the green lights (I forget if it is visible in the video). This is my ultra-fast high voltage protection circuit. The power supply had failed with 24 volts on its output (prior to me getting it). I resurrected it and began the investigation into over-voltage protection circuits. That spawned this video: ruclips.net/video/i85iwemOd-w/видео.html
There are other such things hiding in the background, too. 🙂

[@ornithopterindia]

👍Thank you sir.

[@eie_for_you]

You are welcome! 🙂

[@RensePosthumus]

Nice overflow of the colored shirts ;-) You are working with digits behind the comma for the resistors. In practise that is hard, It would be nice to have a simulation with input from the E24 series (home work for the weekend ;-)).

[@eie_for_you]

Thanks! I changed the shirt colors in post production. 🙂 I simulated the circuit using standard 1% resistor values. You will find the results here:
drive.google.com/file/d/1Q24gEkFUHmkLwMdd_dB3NBtXHruHLjHd/view?usp=sharing
I guess the weekend came early! LOL
Enjoy! 🙂

[@derdoktor7123]

Great videos on cascode BJT amplifiers! Thanks for this. If I‘m not wrong, a dual gate mosfet amp is also a cascode amp. Can you make a video on this topic in the future? I‘m new to RF design and this would be helpful! Thanks again for your work (and for avoiding the left and right turns on your chair 😅)

[@eie_for_you]

Thank you very much! (on all counts). FETs and MOSFETs are on the list of things to do.
Ya know, there are only so many ways to transition from one segment to the next. Maybe switching views without the turn? Working on it. 🙂

[@gregwmanning]

Great learning video Thanks!
I prefer option 2 the feedback resistor, it seems like a very simple addition with a lot of versatility

[@eie_for_you]

The only real downside that I see with it is its dependence on the output impedance of the previous stage. I really *like* that it gives so much more bandwidth. 🙂

[@davidluther3955]

THAT LITTLE GUY IS SO COOL!I WONDERING WHETHER THE COMBINATION OF NEGATIVE FEEDBACK AND,THE SWAMPING RESISTOR IS RESISTOR IS THE BEST WAY TO GO.DOES THE FORMULA FOR THE SPLIT RESISTOR IN THE EMITTOR WORK FOR COMMON EMITTOR, COMMON BASE, COMMON COLLECTOR CIRCUITS?

[@eie_for_you]

That little guy is actually a free image I download from sites that have such things available. The only pictures or videos you will ever see in my videos are either shot by me or available on these free sites like PIXABAY or PEXELS.
This spit emitter equation was specifically derived for the CASCODE amplifier. However, because of the assumptions made in the process of analysis, it will probably also work for the common-emitter amplifier as well. 🙂

[@VorpalForceField]

Very Cool..!! Thank You for sharing Cheers :)

[@eie_for_you]

Thanks, man! 🙂