Edmond Stuart said:
I once read an SF story taking place on a foreign planet. They had motorcycles constructed from a single large wheel with the engine and driver sitting inside the wheel. The wheel running around on a rail around the engine/driver. Now reading again about gyro's, I guess such a monocycle would be hell to steer!
Jan Didden
janneman said:
SF?
Depends on the mass of the wheel and how fast it is rotating. Monocycles have been around for a while already:
http://www.dself.dsl.pipex.com/MUSEUM/TRANSPORT/motorwhl/motorwhl.htm
http://www.dself.dsl.pipex.com/MUSEUM/TRANSPORT/motorwhl/motorwhl4.htm#mcl
G.Kleinschmidt said:
This is quite interesting. McClean says: 'it is steered by leaning out of the wheel'.
But, in watching the McClean V8 video you can see he tries to steer by leaning out of the wheel, but it doesn't work! The thing keeps on going straight!
I guess the secret is to make the rotating part of the wheel as low-mass as possible.
Jan Didden
Hi Jan,
As for stability issues. i.e. weave (0-4Hz) and wobble (4-10Hz), have a look at: http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics#Gyroscopic_effects
It's quite informative.
Regards,
Edmond.
As for stability issues. i.e. weave (0-4Hz) and wobble (4-10Hz), have a look at: http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics#Gyroscopic_effects
It's quite informative.
Regards,
Edmond.
can someone summarise these mechanical analogies on feedback and stability to help us design better electronic circuits?
That was on South Park. The controls were not what I'd want, though.
Andrew, I don't know if those analogies will help build a better amp so much as they serve to better illuminate the operation of feedback and control and perhaps remove the fear factor of less experienced designers from all of the horrible things they've heard asserted about its use.
Maybe silly FET matching question. Many/most? JFET's are symetrical to drain/source flipping. Has anyone tried both ways when matching JFET's? It might not matter enough to be useful.
AD797 model
BTW Scott, how do I qualify myself to get a model of the AD797 at the device level or at least something that reliably predicts the distortion?
Thanks,
Edmond.
BTW Scott, how do I qualify myself to get a model of the AD797 at the device level or at least something that reliably predicts the distortion?
Thanks,
Edmond.
Scott,
> Maybe silly FET matching question.
From you ? 😉
Actually very good question.
> Many/most? JFET's are symetrical to drain/source flipping.
> Has anyone tried both ways when matching JFET's?
Yes, as I had to use the BF862 both ways in my DIP8 discrete opamp. They are "identical" to MUCH better than 5%, probably below 2% (i.e. around 0.2mA for a BF862).
Patrick
> Maybe silly FET matching question.
From you ? 😉
Actually very good question.
> Many/most? JFET's are symetrical to drain/source flipping.
> Has anyone tried both ways when matching JFET's?
Yes, as I had to use the BF862 both ways in my DIP8 discrete opamp. They are "identical" to MUCH better than 5%, probably below 2% (i.e. around 0.2mA for a BF862).
Patrick
"Those were the days"? Is this an old chip or is it that you have been reassigned to shovelling sand into the foundry? 
May I ask a question about the datasheet? It's about Fig 32 and the NFB loop formed by Cn. Based on that simplified diagram, I calculate that the NFB loop gain is = -A.Cc/(Cc - Cn)
Does that ring true?
May I ask a question about the datasheet? It's about Fig 32 and the NFB loop formed by Cn. Based on that simplified diagram, I calculate that the NFB loop gain is = -A.Cc/(Cc - Cn)
Does that ring true?
Scott, now you enter my realm. Should I answer? Probably. Symmetrical Toshiba parts work upside down. However, some RF parts work OK but there is a difference at RF frequencies. Devices with NC geometry for example that make up the 2N5564-6 series favored by Cordell.
Re: AD797 model
They're working on that for but it's going to be a long time. There is a pie in the sky proposal for automated entry of sims to run on a compute farm here and only return the results to the customer.
They would be full models so if there was any FM distortion it would be there. Repeat Barrie's computation at 100MHz GBW and you will see what you are dealing with.
Edmond Stuart said:
They're working on that for but it's going to be a long time. There is a pie in the sky proposal for automated entry of sims to run on a compute farm here and only return the results to the customer.
They would be full models so if there was any FM distortion it would be there. Repeat Barrie's computation at 100MHz GBW and you will see what you are dealing with.
Re: Re: AD797 model
Good idea, especially in off-line mode: trained technicians can solder and measure then put real results in the file. 😉
scott wurcer said:
Good idea, especially in off-line mode: trained technicians can solder and measure then put real results in the file. 😉
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