OT: milestone, the x-Chapters

Last night we handed over finished latex and eps files, for AoE The x-Chapters, to our long-suffering editor at CUP.

Amazing stuff * went in during the last 10 days, plus I get to make submissions and corrections for maybe three more weeks, while the files are being processed. The draft pdf version has over 650 pages.

  • Hundreds of explorations and explanations of exotic engineering stuff you need to know. * A dozen varied examples of using power MOSFETs to solve difficult linear-circuit problems. * A neat TIA amplifier with an 8-decade dynamic range, 12-bit precision, not a log converter! Example use: a starlight to sunlight digitizer. * A true DC transformer. Keep your extra energy. * Control your piezo with charge, not voltage. * 1.2kV HV amplifier, with DC-to-1MHz range. * 100V 5A DC-10MHz 1000V/us power amplifier. * More light, pulse your LED at 200 amps. * Fast 1.5kV 2pF floating current source. * Hundreds of other cool things, too tired to type, need sleep.
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 Thanks, 
    - Win
Reply to
Winfield Hill
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Congrats, I'm looking forward to purchasing a copy. Do you know the (very approximate) publication timeline?

Reply to
Steve Goldstein

Yes, everything is tuned for a Dec 1st release.

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 Thanks, 
    - Win
Reply to
Winfield Hill

Let's see, 10V out, precision feedback resistor, 10uV input opamp voltage offset, 6-decade range, with 100% error at the bottom. Raise output to 100V with amp, feedback resistor there, 7-decades. How get 8 decades with 1% precision (10-decades)? Maximum current 5mA, minimum FS = 50pA, for 1% max Ioffset 0.5pA, check! Maximum Voffset 100V/10^10 = 0.01uV, no way! Change range resistors, not allowed? Sheesh! We reveal the secret, a clever, easy-to-use solution, but it wasn't our idea!

Hint, starlight to sunlight circuit, 15 parts: three opamps, eight Rs, two Cs, and two JFETs. The input opamp is an LMP7701, Vos = 200uV Ib.

uP. 60pA (10% is 6pA) to 3mA, 5 x 10^8 range. Can you do it?

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 Thanks, 
    - Win
Reply to
Winfield Hill

Well only if I'm allowed to change feedback R's. :^)

So what's the trick?

Nice to hear this is in the works. I'll put it on my Xmas wish list.

George H.

Reply to
George Herold

Progressive amp saturation? That's fun.

You can dump both ends of a photodiode into two TIAs, with different gains. There are also other uses for that idea.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Yes, that's cute, but this one needs more range.

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 Thanks, 
    - Win
Reply to
Winfield Hill

Nope, only one input stage allowed, and it takes all the photo-current. You can play games with the feedback resistor, but you're not allowed to disconnect one and connect another, with a switch, because that'd interrupt the measurement.

Sometimes, once you know something is possible, you can figure out how to do it. But I don't think I could have solved this puzzle, even with that knowledge. Once I saw it done, I had to think carefully to understand it. But others are smarter than me, and may get the answer.

--
 Thanks, 
    - Win
Reply to
Winfield Hill

On a sunny day (24 Jun 2019 09:45:42 -0700) it happened Winfield Hill wrote in :

You would not be using a JFET as AGC element?

Reply to
Jan Panteltje

Congratulations!

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

Sure. Run the PD open circuit and measure the voltage. Back in 1990 I built a beam aiming detector that I still use based on that trick. It uses a Ge quad cell and uses two op amps to form V1-V3 and V2-V4. Two centre-zero, edge-reading taut-band panel meters read X and Y.

It works over about four decades of photocurrent because the shunt resistance of the Ge quad cell is the pits, but I've used it from < 400 nm to >1600 nm.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

Suppose you build a TIA with high gain. When it rails, one could diode-couple the (former) summing point into the next, lower gain TIA. With very good diodes of course.

Or connect the first summing point into an emitter or a fet source, which would conduct when the TIA gives up. Similar idea.

Or use a nonlinear breakpoint thing in a TIA feedback.

What do you have against log amps?!

--
John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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Reply to
John Larkin

The PD already comes with a free one . ;)

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

As an AGC, no, could that be accurate to 1% or better?

--
 Thanks, 
    - Win
Reply to
Winfield Hill

Can't see how any of your ideas could be made to work to 10% 1% let alone 09.1%, exactly. Getting close maybe, but no cigar.

--
 Thanks, 
    - Win
Reply to
Winfield Hill

We want 1% or 0.1% accuracy, linear, no tempco.

--
 Thanks, 
    - Win
Reply to
Winfield Hill

Accurate to photocurrent, to 1% or 0.1%, no tempco?

--
 Thanks, 
    - Win
Reply to
Winfield Hill

Build 3 TIA's, different gains, when the lowest rails you switch to the next one?

George H.

Reply to
George Herold

You aren't getting 0.1% over 8 decades with 12 bits. Your step size is 0.45%.

You can make a feedback square-rooter using the two FETs as a PWM multiplier.

Cheers

Phil Hobbs

Reply to
pcdhobbs

The technique can do 1% of a 10^-8 signal.

Wrong. Keep thinking, you can, if you use multiple channels. OK, let me think and calculate more carefully. The starlight- to-sunlight version, with 15 parts, is a simplified version, it's good to about 1%, degrading somewhat at the bottom of a range. OK, another hint, there are simultaneously- overlapping ranges. But no range changing.

--
 Thanks, 
    - Win
Reply to
Winfield Hill

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