tuning an LC

Except that it doesn't transduce anything. Therefore it's simulated. Just as flight simulators don't actually fly. Capiche?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs
Loading thread data ...

A better word for it is "emulation". ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   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

On a sunny day (Thu, 21 Nov 2013 12:43:50 -0500) it happened Phil Hobbs wrote in :

Sorry that does not parse here.

Usually no, sometimes yes.

Reply to
Jan Panteltje

On a sunny day (Thu, 21 Nov 2013 10:47:42 -0700) it happened Jim Thompson wrote in :

Yes.

Reply to
Jan Panteltje

We're measuring Theta-ja in a manner that's mostly independent of actual temperature. There are some second-order effects that we could correct for, but it's pretty good as-is.

I was impressed myself.

Our modules plug into commercial VXI crates that have fans. We don't furnish those crates. We want to measure air velocity at our module and report that to the users, so they can tell if a fan fails or if air flow is blocked or inadequate or something.

We put the parts on the board layout, figuring that, if it actually worked, we could provide the air flow register and advertise the feature. It works pretty well.

Jan could do that on his airplane maybe, if he can afford a few hundred mW of power.

--

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

--
Yes, John, it's called "pro bono".
Reply to
John Fields

Gosh, I thought this was an electronics discussion group. Is it bad form to introduce topics to discuss?

Since you never do, maybe it is a bad thing to do, to start technical threads. We should follow your example and restrict ourselves to redneck political rants and wine rack repairs.

It's called "designing." It involves exploring various possible solutions, some conventional and some goofy. I'm doing it in public.

Why don't you design something and open it for discussion?

I've got an intern working on that now. Grunt work, ideal for an intern.

I thought I mentioned that, when you suggested the variable inductors. Under an ohm is OK. I might add a zero-ohm jumper, just in case the customer ever wants to kill the Q.

--

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

Call it whatever you like. To my ear, "emulation" sounds more like a digital thing. Someplace I probably still have a PIC 17C456A ICE, for instance. Hanging a gyrator on a capacitor gives you what everyone calls a "simulated inductor", so I claim that it's more idiomatic to call this a "simulated transducer" than an "emulated transducer".

If somebody giving an active filter talk was going on about "emulated inductors", everybody in the audience would be chuckling.

Of course, after 200ish posts, the gist of the matter has been clear for some days now.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

--
My guess would be - if it's real - that it's something like a 
powered resonant proximity sensor used to detect "gear teeth" as 
they go by, with 170000 teeth per second being the result of the 
desired wheel speed. 
  
JF
Reply to
John Fields

In this thread, isn't Larkin emulating a transducer... that is...

...IMITATION? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   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

Variable-reluctance sensors usually use DC drive and detect AC, I think, and it would be strange to need 50V swing for that. My guess is that it's a magnetostrictive drive, and they're using the resonance to match the acoustic impedance of whatever it's driving. But we don't know for sure.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

--
How so?
Reply to
John Fields

You know, Jim, it would really be better to just admit that

1/2 (30 mA)**2 * (any plausible wiring inductance) won't produce much amplitude across the ~20 pF drain capacitance of a 2N7000.

Say we take L to be 1 uH, which is about the inductance of a 1-foot diameter loop in free space.

E_L = 0.5*1e-6*(30 mA)**2 = 450 pJ.

This, when deposited on a 20 pF drain capacitance would be

V_d = sqrt(2*450 pJ/20pF) = 6.7 V,

and that isn't even counting the self-capacitance of a piece of wire that big, which would be of the same order.

The 2N7000 is a 60-volt FET. You'd need a loop half the size of a football field to blow it out at 30 mA, even if it had no capacity whatsoever to absorb a nanojoule avalanche nondestructively.

When you lose your temper like this, you say silly things that you wouldn't say otherwise, and you make yourself look bad. As the wise man said, "When you find yourself in a hole, stop digging."

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

I explained it. No point to doing it again.

--

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

What's this have to do with "emulation" (this thread)?

And there are lots of other scenarios... what's 1uH with 1Amp dumped into 20pF? ... It's 158V

Why the resistance to good engineering practice, rather than squatting and saying, "you can get away with..."?

But I guess that's the way you do things? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   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

A la "Red October" ?>:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   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

Calculating rather than spouting off? Yes, absolutely.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

And ignoring my 158V ?>:-}

I think it's time for _you_ to stop digging ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   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

--
Not at all.
Reply to
John Fields

Your 150V is just fogging--you pulled that number out of your, um, lower back.

The point at issue was 30 mA for a relay, not an automotive ignition, or a contactor, or a pyrotechnic igniter. That 6.7 volts isn't much like a kilovolt in my lexicon. It isn't even 1% of a kilovolt.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

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