1. Home
  2. Electronics Design
  3. Poor Man's Gyrator

Poor Man's Gyrator

Shedding my horns of anger at punks (young and old) who have no engineering/math clue, and donning my professorial hat...

formatting link
...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

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

Reply to
Jim Thompson
Loading thread data ...

The summing point of a simple TIA (opamp, feedback resistor) looks like an inductor.

--

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

But not one that's at all well controlled.

--
My liberal friends think I'm a conservative kook. 
My conservative friends think I'm a liberal kook. 
Why am I not happy that they have found common ground? 

Tim Wescott, Communications, Control, Circuits & Software 
http://www.wescottdesign.com
Reply to
Tim Wescott

On Wed, 23 Jan 2013 15:56:10 -0600, Tim Wescott wrote:

Right, it depends on the amp's GBW.

Wiki has a fake inductor

formatting link

My version is below. The parasitics resistances are in parallel with the inductance, not in series. All have the same number of parts.

Version 4 SHEET 1 880 680 WIRE -240 -128 -272 -128 WIRE -224 -128 -240 -128 WIRE -112 -128 -144 -128 WIRE -96 -128 -112 -128 WIRE -272 -96 -272 -128 WIRE -144 -96 -144 -128 WIRE -272 0 -272 -16 WIRE -144 0 -144 -16 WIRE 16 32 -32 32 WIRE 176 32 96 32 WIRE 336 32 176 32 WIRE 176 80 176 32 WIRE 288 160 256 160 WIRE 304 160 288 160 WIRE 256 192 256 160 WIRE -144 208 -272 208 WIRE -32 208 -32 32 WIRE -32 208 -144 208 WIRE 16 208 -32 208 WIRE 176 208 176 144 WIRE 176 208 96 208 WIRE 224 208 176 208 WIRE 336 224 336 32 WIRE 336 224 288 224 WIRE 384 224 336 224 WIRE 400 224 384 224 WIRE 224 240 176 240 WIRE -272 256 -272 208 WIRE 176 288 176 240 WIRE 256 288 256 256 WIRE 288 288 256 288 WIRE 304 288 288 288 WIRE -272 352 -272 336 FLAG -272 0 0 FLAG -144 0 0 FLAG 176 288 0 FLAG -272 352 0 FLAG -240 -128 +15 FLAG 288 160 +15 FLAG -112 -128 -15 FLAG 288 288 -15 FLAG 384 224 OUT FLAG -144 208 L SYMBOL res 112 16 R90 WINDOW 0 -21 88 VBottom 2 WINDOW 3 -48 39 VTop 2 SYMATTR InstName R1 SYMATTR Value 1K SYMBOL Opamps\\UniversalOpamp 256 224 R0 SYMATTR InstName U1 SYMBOL voltage -272 -112 R0 SYMATTR InstName V1 SYMATTR Value 15 SYMBOL voltage -144 -112 R0 SYMATTR InstName V2 SYMATTR Value -15 SYMBOL current -272 336 R180 WINDOW 0 54 38 Left 2 WINDOW 3 -250 27 Left 2 WINDOW 123 -152 68 Left 2 SYMATTR InstName I1 SYMATTR Value PULSE(0 1m 10u) SYMATTR Value2 AC 1m SYMBOL res 112 192 R90 WINDOW 0 74 85 VBottom 2 WINDOW 3 47 33 VTop 2 SYMATTR InstName R2 SYMATTR Value 10K SYMBOL cap 192 144 R180 WINDOW 0 65 47 Left 2 WINDOW 3 58 13 Left 2 SYMATTR InstName C1 SYMATTR Value 10n TEXT -256 72 Left 2 !.tran 2m TEXT -296 128 Left 2 !;ac dec 10 1 1e7 TEXT 8 -112 Left 2 ;Fake Inductor TEXT 16 -72 Left 2 ;JL Jan 2013

--

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 a plain OpAmp with feedback resistor is inductive.

Not something you or I would build.

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

    ...Jim Thompson
   |    mens     |
  |     et      |
 |
      |

I think if you invented a poor woman's vibrator you would sell more of them.

Reply to
brent

Now that I think about it, that could be handy in a couple of situations.

--

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

When I was getting started in electronics, (long before I joined the dark side and went for software full time,) read several articles showing gyrators in simulated percussion instruments.

Basically, a simple LC resonant circuit, (real C, simulated L,) as an electronic version of Bongos.

I guess digital sampling and DSP's did away with the need for this type of circuits. (Never saw a giyrator with less than 4 or 5 opamps, though.)

--
Roberto Waltman 

[ Please reply to the group, 
  return address is invalid ]
Reply to
Roberto Waltman

The single-opamp example I posted above looks like about 150 mH in parallel with

1K. Usable for audio. The values can be tweaked to get other Ls and Rs. It has the property of a true inductor in that, when it's shorted, the current is constant but indeterminate. Well, with an ideal opamp it is.

It's easier to simulate an L to ground than a floating L, so one opamp works.

But yeah, audio can be all DSP. I like picosecond electronics, where circuits are still fun.

--

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

If you follow any threads on that subject, the women all sound like Tim Taylor, more power, more power!

Reply to
amdx

Here's a 2 OpAmp method I've been using for around 40 years...

formatting link

formatting link

formatting link

formatting link
...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

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

How this is different from a trivial one-opamp gyrator ?

formatting link

Vladimir Vassilevsky DSP and Mixed Signal Consultant

formatting link

Reply to
Vladimir Vassilevsky

As I drew it, it replicates the structure in...

Message-ID: Subject: Cute amplifier - bootstrapped From: snipped-for-privacy@yahoo.com

Your version shows some inductance, but I think lacks the Q of the one I analyzed. ...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

His puts both resistors in series, and under-utilizes the opamp.

--

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

The 'Q' of this group is very low, some days. :(

Reply to
Michael A. Terrell

Some of these posters are like a wife... totally wrong, but insistent that they are correct.

The worst part of it, these posters want me to treat them like I treat my wife... tell them they are correct and pat 'em on the ass.

It ain't going to happen >:-} ...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

I see... domestic difficulties are what make you so nasty.

Condolences.

--

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

There isn't enough hand sanitizer on earth!

Reply to
Michael A. Terrell

"John Larkin":

With gyrators, Q is the matter of component values. Sometimes it is convenient to use simulated reactance, especially as it could be nicely adjusted in very wide range by changing amplifier gain. Not so obvious problem with gyrators is noise.

Vladimir Vassilevsky DSP and Mixed Signal Consultant

formatting link

Reply to
Vladimir Vassilevsky

See...

formatting link
...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

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.