+/- 5 vdc signal to 0-10 vdc signal

--- View in Courier:

-- JF

Good grief. An LM318. Why? Farnell still stocks them, but they always were noisy and cranky. I never used one after the LF356 came on the market around 1974 - the LF356 wasn't quite a fast, but it was quiet and well behaved.

If you need real speed these days, the LM318 isn't remotely interesting.

--

e a

So why suggest an obsolete and cranky - but moderately fast - op amp to do the job?

The 741 is the traditional part for this sort of work - I prefer the OP-07 because it has no vices and a low offest voltage, but without some detail about the application you can't go very far.

-- Bill Sloman, Nijmegen

here a

Since my skills aren't obsolete, the description doesn't fit me at all well; I've been tackling system design and analysis problems all through my career. The optimal solutions keep on changing as the technology progresses, so I'm forever finding out about new techniques and new components, rather than sticking to the stuff that worked when I started in on electronics, when the NE555 and the LM318 were new and modrately exciting.

Your sorts of skills are presumably in demand for museums of technology where you can tell school-children about stone age electronics, next to the guy who makes Folsom points by bashing one bit of rock with another.

Many of the example circuits in the data sheet have 5pF in parallel with 10k feedback resistors - it looks as if you can get away without it at a noise gain of two, which corresponds to your circuit, but the circuit won't settle fast without it, and you'd need another 5pF (or whatever) in parallel with the 10k to +5V, so your mileage does fall a little short.

You may think that it is a trivial error to specify an wildly unsuitable amplier in an answer a dumb newby question. It wouldn't look trivial to the poor sucker who took your advice as gospel and then had to spend a week learning how to stop a fast amplifier from oscillating.

-- Bill Sloman, Nijmegen

If ultra-high input impedance is a consideration and you have dual supplies then something like this is along the same lines: View in a fixed-width font such as Courier.

. . . . . . .---[10k]-----------. . | +15 | . | |\\ | | . Vin>--+--------[3.3k]--|+\\| | . | | | >---+->Vo=Vin+5 . [10k] +------------|-/| . | | |/ | . '---+-[15k]-+-[15k]-+ . | | | . [15k] === -15 . | |0.22u . +-------' . | . -+- . /// . . . . .

That's no one's fault but yours for not even reading up on the latest components and doing designs just to stay in practice. You had no reason to find a job, and were too lazy to remain useful.

st

Do read what I wrote. I do read the trade literature to find out what is going on. I don't do paper designs just for the exercise - it's a waste of time without a real problem to constrain your choices - but when a new component takes my fancy I do rough out how it might solve an old problem.

You are welcome to your delusions about my situation - somebody like you who is in constant pain does need some kind of distraction (no matter how bizarre), and Central Florida isn't exactly the entertainment capital of the world, now that Jeb Bush isn't around winning elections for his brother by purging Democrats from the electoral roll.

-- Bill Sloman, Nijmegen

Yes the pain is 'so bad' that I go two or three days at a time before I absolutely have to take gabapentin for the diabetic neuropathy and only when I can't get to sleep at night. The rest of the time I can manage the pain without medication. What's your excuse?

Yawn. Keep lying to yourself, Bill. No one really expects anything else from you. It speaks volumes that you found Jeb Bush entertaining. I'll bet you just LOVE root canals and having a colonoscopy.

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Keep lying about me Michael - it's just one more way for you to demonstrate how out of touch with reality you really are.

Dutch dentists use local anesthetics - root canal work is just boring, but I can sleep in a dentist's chair, which helps to pass the time.

Those of my relatives who have been subjected to colonoscopy didn't enjoy it much, but didn't find it traumatic. I'm due to swallow an endoscopic ultrasound transducer in a couple of months so that my cardiologist can examine my heart from my eosophagus - a transesophageal echocardiogram

I'll be delighted to get a chance to look at the transducer and the images - I worked on echo cardiography from 1976 to 1979 and really enjoyed it - though swallowing the transducer isn't going to be too much fun.

-- Bill Sloman, Nijmegen

e:

It isn't an insult, but a description. The circuit that he wanted can be found in any decent text-book.

When I post questions over Linux, I have characterise myself as a dumb newby, because in that area I need dumbnewby level explanations.

Dream on.

More self-delusion.

You don't understand them so you soothe your ego by persuading yoursefl that there isn't anything there to understand.

Or any more. Your opinion on this subject is worth about as much as your opinions on non-trivial electronics.

With the - inappropriate - op amp you chose, the circuit needs two extra capacitors (somewhere around 3p3F). The fact that you don't seem to appreciate this illustrates the (negligible) depth of your electronic expertise.

Picking an offset voltage and a resistor ratio that will work isn't exactly rocket science. The only reason that I didn't do it was that you'd already posted an acceptable solution which does illustrate the point that it isn't difficult.

Not that you'd know how. You may claim that you can design precision circuits, but I can't remember a single post of yours that evidenced this hypothetical skill.

Dream on.

-- Bill Sloman, Nijmegen

Yawn. You think that you are worth a lot more than you really are. As far as lying? You are an expert, making ASS-umtions about people that you've never met. No one beleives 90% of what you say. You presume to know everything about my medical problems, and you know almost nothing. I would tell you to get a life, but you've already wasted one.

Try it sometime in an emergency situation where there is no pain killer availble, then get back to me.

Why not? You expect us to belive eveything you say.

Something is worth what somebody will pay for it. No local employer is willing to hire me, so I'm not worth anything. That doesn't leave me much room to think that I'm worth more than I really am.

As do you.

You can speak for the whole world? Like I said, you are a little out of touch with reality.

st nothing.

Where have I claimed any detailed knowledge of your medical problems? =46rom time to time I echo the claims that you make about your medical problems, and I've no reason to beleive that you lie about them, but I've got no independent source of information about them either.

Why not? It does happen to be true.

-- Bill Sloman, Nijmegen

nothing.

Yawn.

rote:

"Ignorant" is a multisylabic word and correspondingly unlikely to show up in idiomatic expressions. The phrase "dumb newbie" is an idiom - google finds 28,700 hits - which conveys exactly the same idea, and is easier to type. If you were fluent in proper English - as opposed to your impoverished Texan dialect - you'd be aware of this.

Sadly, the ignorance is all yours.

In that context it is most certainly appropriate!

Getting excited about a typo again? You really are grasping at straws.

Now you're just being modest.

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