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Cute amplifier - bootstrapped

The "bootstrap" cap DOES NOT "turn Q1's collector resistor into a virtual current source."

So it's NOT "neat".

The impedance at the collector of Q1 is...

(R1 + R2 + R1?R2?C1?s)/(1 + R1?C1?s/(gm?RT + 1)) (where RT = R3 + R4)

That doesn't look like a current source to me. (*, see below)

I'm not the one being unpleasant. It's you. Why are you digging in your heels, when your explanation is wrong.

Digging in your heels is not very professional.

Only when you (and other Larkin sycophants) dug in their heels, did I become insistent on the proper analysis and explanation.

I've presented some math and some simulations, yet you still dig in.

I guess you've decided to be "dagmarbadboat" >:-}

BTW, I knew Dagmar, she was from my hometown. Her father was a barber and ran the illegal gambling in the back room ;-)

(*) I was in course VI-B (EE Honors) at MIT, so I had my loop and nodal analysis from Harry B. Lee...

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se I didn't have to endure the 1H, 1F, 1 Ohm world of Ernst Guillemin...

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If you're still insistent, why don't you show me where I'm wrong?

Really poor form, dagmarbadboat :-(

Tick-Tock >:-} ...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.
Reply to
Jim Thompson
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The circuit, as presented, has faults.

You apparently haven't followed all the subthreads, and viewed my analyses and simulations. ...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.
Reply to
Jim Thompson

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Fred, Things are not what they seem. The input cap phase shift is calling the shots. See the (new :) last page where I DID vary the "bootstrap" capacitor....

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It's one of those circuits that fool some folk.

Don't get sucked in by Larkin or dagmarbadboat... check things out for yourself. Remember what your mother said about "birds of a feather", and "you're known by the company you keep".

Now Larkin or dagmarbadboat will jump in here and change the source impedance, but dagmarbadboat already claimed "low impedance".

Keep you hands in your pocket and you can never be accused of "hand-waving" >:-} ...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.
Reply to
Jim Thompson

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That must make you feel right at home :)

Jamie

Reply to
Jamie

Still no analysis to prove the claims. ...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

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| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Reply to
Jim Thompson

Well, it looks like you win. Nobody is going to top your 500 kilovolt output from a couple of 2N5089s.

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--

John Larkin         Highland Technology, Inc 

jlarkin at highlandtechnology dot com 
http://www.highlandtechnology.com 

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom laser drivers and controllers 
Photonics and fiberoptic TTL data links 
VME thermocouple, LVDT, synchro   acquisition and simulation
Reply to
John Larkin

Just what do you want me to explain? The 23 dB gain increase at the frequency of interest? Or that the bandwidth doesn't significantly change when you increase C2 because C1 into Q1 is a high pass filter?

Make both of them 100uF and you have a 'cute' audio amp with 25 dB more gain (20-20kHz bandwidth < +- 1 dB) than if you remove C2.

Fascinating how you can look at 480V vs 34V ('eyeballing' your graph, which matches my sim) and claim 'no net gain'.

How about the blind man who can't distinguish 480 from 34?

Reply to
flipper

Blind man.

Input high pass filter and limited high end response of the transistors.

Change C1 and it won't 'look resonant'.

Reply to
flipper

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Moron! In that last graph the output is peaking at FOUR HUNDRED VOLTS.

Obviously something is bad, bad wrong.

--

John Larkin                  Highland Technology Inc 
www.highlandtechnology.com   jlarkin at highlandtechnology dot com    

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom timing and laser controllers 
Photonics and fiberoptic TTL data links 
VME  analog, thermocouple, LVDT, synchro, tachometer 
Multichannel arbitrary waveform generators
Reply to
John Larkin

How is he getting 480 volts from a 25 volt transistor? Or 500 kilovolts, for that matter.

His sim is seriously messed up.

--

John Larkin                  Highland Technology Inc 
www.highlandtechnology.com   jlarkin at highlandtechnology dot com    

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom timing and laser controllers 
Photonics and fiberoptic TTL data links 
VME  analog, thermocouple, LVDT, synchro, tachometer 
Multichannel arbitrary waveform generators
Reply to
John Larkin

Sorry but 'virtual current source" is the classical conceptualization of what's taking place, just as a 'large V through a large R' is.

Simply look at R2. Signal is on the collector end and the same signal (if the emitter follower were perfect) is on the C1 end. With the same AC voltage on both sides the net AC current flow is 0 (if the emitter follower were perfect), which 'appears' to be an 'infinite' impedance (Vac/0) and that is 'like' a current source.

Of course, the emitter follower is not perfect so the real world result is somewhat less than infinity ;)

It's also in parallel with the effective impedance into the emitter follower base, which further reduces the effective collector load impedance.

You get a 25 dB gain increase with no additional active components and in an era where tubes were quite expensive that's 'neat'.

Neither is obfuscating a rather simple concept.

Reply to
flipper

What, "flipper", are you joining the sycophants... change the circuit and then claim it was good all along.

It's SHUNT FB. Do you know what that is? ...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.
Reply to
Jim Thompson

Actually do the simulation, then stuff it up your arse. 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.
Reply to
Jim Thompson

No it's not and he's not 'getting 480V' from anything. That's simply a voltage gain vs frequency plot.

I usually plot in dB but mine can be set to 'magnitude' as well and the results are the same.

Reply to
flipper

I didn't 'join' anything. Just providing some explanation for the observed behavior.

I did no such thing. I first explained why the EXISTING circuit does what it does and THEN provided a mechanism one can use to confirm it.

Yes. Do you know what a high pass filter is?

Reply to
flipper

I already did, and long before you.

Now YOU explain why, to your eyeballs, 480 is 'not more' than 34.

Reply to
flipper

It says volts.

How about the 500KV number? What does that mean?

--

John Larkin                  Highland Technology Inc 
www.highlandtechnology.com   jlarkin at highlandtechnology dot com    

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom timing and laser controllers 
Photonics and fiberoptic TTL data links 
VME  analog, thermocouple, LVDT, synchro, tachometer 
Multichannel arbitrary waveform generators
Reply to
John Larkin

Certainly! I tried to make that point in...

Subject: Re: Cute amplifier - bootstrapped Date: Sat, 19 Jan 2013 11:33:52 -0700 Message-ID: ...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.
Reply to
Jim Thompson

What a dummy. And Obfuscator. Do you think you can out-obfuscate Larkin ?:-) ...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.
Reply to
Jim Thompson

Don't mind Larkin, he's just seriously ignorant. ...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.
Reply to
Jim Thompson

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