Here are links to the surrounding pages of Self's book. The gain is supposed to be about 3 in all cases, I gather. He starts with a simple amp and makes incremental mods, displaying some graphs to illustrate the discussion:
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I think this is fair use of the copyrighted material. It should provide much better context.
I suppose a capacitor in series with an inductor can simply be considered an "AC short" at the "frequencies of interest" ?:-)
And you deny that it looks inductive?
And you deny that it actually goes resonant in the overall circuit when driven from (as described by the OP) "a low impedance source"?
You're just one of many in this crowd who thinks engineering is hand-waving and opinion and application of generalities.
Sorry, but it's an exact science, whatever opinions you want to throw up... and I mean it as exactly that... vomit >:-}
Don't go away mad, just go away. You've proved yourself incompetent.
?Here's a dime. Call your mother. Tell her there's serious doubt about your becoming [an engineer]." (*)
(*) Courtesy of Prof. Kingsfield in the "Paper Chase" >:-}
[snip] ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Not off hand. Everything 'easy' to find on google is about modeling the transducer mechanics itself or ultra elaborate models
You keep saying that but it's a matter of scale and source impedance. I model it with 1mVrms in, for around 450mVrms out, and since source impedance is low there's 970uVrms on the base. So it isn't 'held constant' relative to the signal amplitude, which is what 'matters'.
Of course, anything that can be modeled with voltage sources can be modeled with current sources, and vice versa. I just don't think a cap shunt to ground, effectively erasing all signal at precisely the frequency it should 'be there', makes sense.
Well, don't get too carried away because C obviously changes too when the plates are moved but that's not going to show up in the 'simple' model, nor does it significantly matter for small delta C.
No, and you don't have a "capacitor in series with an inductor." You have a capacitor, period, and at the frequency of interest that IS a short to ground.
Not at the frequency of interest is doesn't.
Right, it doesn't. It's simply the frequency response of an amp with a high pass filter on the input that then rolls off because it's frequency response can't go no higher. As I told you the first time you blurted that nonsense, put a bigger caps in both places and that mysterious alleged 'resonance' will turn into a broadband response.
No, I'm just someone who knows how a bootstrap works.
People have been using bootstraps for over a hundred years so it's you who needs the 'dime'.
Speak louder, flipper! Fill the room with your intelligence!
Your assignment is to write (by hand) a complete analysis of the "Cute" amplifier.
If you can't do it, you will become a non-person.
I'm betting you can't do it without hand-waving and making incorrect assumptions about capacitors.
So, Speak louder, flipper! Fill the room with your lack of intelligence! ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
It doesn't really matter because Jim has backed himself into a corner and, at this stage, is going to deny the concept no matter what. Although, it might be fun watching him try to explain how the dc coupled bootstrap is 'resonant'.
It's not "DC-coupled" and you've ignored all the analyses and simulations I've shown. I'm speaking of the "Cute" amplifier, Self's values are more likely chosen properly.
Show me your analysis of "Cute" or go away.
You can't, so you'll do a Larkinesque twist and turn, trying to evade doing the analysis.
Pretty sad, you can't even do a sophomore level loop and nodal analysis.
So, Speak louder, flipper! Fill the room with your lack of intelligence! ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Speak louder, flipper! Fill the room with your lack of intelligence!
The Op said the source was low-Z, so it's as I analyzed.
Show us your analysis dumb-f*ck.
You can't, so you'll try all kinds of nonsense to evade demonstrating your ignorance.
Post no more at me... you're out-of-here.
You've plainly proved you can't do the analysis... so you're punk level. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
No problem for me... I've already found a proper model.
Big problem for you... you can't do the analysis.
And you're too stupid to understand. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Your ignorance is underwhelming. You totally don't understand the analysis.
If you could, you'd jump right to trying to prove me wrong... but you can't. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
How it works, and why, has already been explained to you. It's also been explained that shorting the input signal to ground is not a 'good' simulation and since you can't grasp any of it there's not much reason to bother with you any more.
You can either figure it out, or not, but the fact is it works.
You DO understand that I'm going to hang you to "ground", don't you ?:-}
What a dummy. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I find it difficult to assume he's really that ignorant. If his abilities at circuit analysis are as bad as he exhibits in his posts... wow :-(
The OP did say that C2 was indeed the transducer.
I've located several papers that address modeling a capacitive transducer. They tend to be really wild, including case resonances, etc., but I'll try to reduce them to a usable behavioral model. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I would have no problem with an 'equivalent' model but, as implemented by JT, they are obviously not 'equivalent' since they produce wildly different results, which is pretty much the definition of 'not equivalent'.
What an acceptable model 'is', regardless of whether it's Thevenin or Norton, is precisely the question at hand.
Now, consider his 'current source' model. It's an AC current source into a capacitor to ground, the junction of which is the 'signal' into the base of Q1. However, at 40 kHz 98% of the current source's AC signal goes through the cap to ground and, just so there's no confusion, that is entirely independent of amplifier topology.
So even if one knows nothing about 'capacitive transducers' you can still ask yourself: would anyone design a 'capacitive transducer' in which there's essentially 'no signal' at the intended frequency of operation? Furthermore, does it makes sense to you that a 'capacitive transducer' has maximum output at low frequency but virtually none at the frequency of operation? So why would anyone excite it at 40 kHz when there's 16 dB more signal at 100 Hz?
A simple sanity says the 'current source' model doesn't work but JT is so married to his original misunderstanding of the 'bootstrap' that he's lost all rationality and it is, quite literally, impossible to even discuss it with him. Observing the plainly obvious is now 'stupid' and he needs a 'node analysis' to see that a cap to ground is effectively a short at 40 kHz.
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