Yep, way to go. It doesn't get much cheaper than that if one of those three-pin shunt regulators fits your bill WRT accuracy and drift. And there can't be no opamp offset if there ain't no opamp no more.
-- Regards, Joerg http://www.analogconsultants.com/
et
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Okay- well you could do something like this to get a pure zero, there are o= ther things you can do with transconductance amps, since C can be fairly sm= all, no compensation is needed on that buffer:
Please view in a fixed-width font such as Courier.
. . . . . . Vo . OUT>-----------------------+----------- . | . .--+--. . | | . [R] =3D=3D=3DC . | | . .---------+--+--' . | | . | |\ | . '---|-\ |< . | >---| . Vref----|+/ |\ . |/ | . | . | . | . If
He probably used pots for all the resistors too. ;)
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 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
ha. I learned to use a slide rule back then. My last year in tech school I managed to get one of the first TI calculators with the small bubble LED array display and snap keys. In college I got a radio shack blue read out display with real coil spring buttons on it, I loved that one but my oldest decided to use it one day and left it on the floor for people to walk on. I Still have the TI, however :)
I then collected some HP desk calculators.
The previsions I was talking about mostly was places to insert caps and compensation networks if needed. on board pots were used in places know unstable voltages were to be. Back then, resistors was like a crap shoot.. THey are much better today!
Jamie
Youngster! My first calculator was an HP35, which cost $400, back when I was making $400 a month. I still have it.
I have two 9100s, the first HP calculator. They weigh about 40 pounds, have CRT displays, and have no ICs inside: all discrete transistors. I really want to get them working, but HP has never released the schematics.
-- 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
Hmm, I bought my HP45 in October of '73, when I was making $2.25 an hour, max
20hrs per week (I worked as a tech for the university and they wouldn't let me work more). I still have it. I ran across it a couple of weeks ago but I'm sure it's packed, somewhere. ;-)Should put them in the Smithsonian. ;-)
I've done the opposite, several times. I'll often use a 74xx1Gxx instead of a transistor. It's often cheaper, smaller, and lower power. OTOH, I've recently found some NPN-PNP self-biased pairs that are pretty cheap. They make great level shifters.
Depends. Size and parts count is often more important.
A few months? Like? (besides Maxim ;-)
I still have my wife's HP11C. Using it every workday and even then a set of batteries will last many years. I wish HP would find its way back to what their old folks were capable of.
[...]-- Regards, Joerg http://www.analogconsultants.com/
The 11C was the best calculator HP made. Someone swiped mine. :-( I have an
11C clone on my smart phone which does it justice (I think the screen is a picture of an 11C), except for the buttons; no click.
the
me
And after four days the low-batt warning comes on :-)
-- Regards, Joerg http://www.analogconsultants.com/
the
me
I have that problem with a couple of newer TI-82, 83's.. I remove one cell when not in use.
Jamie
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No, the original HP35 was the best, assuming you don't want programmability. I don't like the "landscape" layout of the 11.
The 35 is a real engineer's calculator: pi is in plain sight.
-- 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
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Days??? Actually, it rarely comes on. It gets charged every night. ;-)
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I loved it and as Joerg alluded, the batteries last *years*. I think I had mine ten years and only replaced the batteries once. I replaced the
*rechargeable* batteries in my HP45 more often than that.The 45 was far superior. Polar-rectangular and polar arithmetic was a snap. I used that a *lot* my senior year of college. ;-)
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My HP11C gets charged about once every 10-15 years. Courtesy of CVS, six bucks or so for three thick coin cells.
-- Regards, Joerg http://www.analogconsultants.com/
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But it makes a lousy WiFi hot spot. ;-)
Am 02.06.2012 23:05, schrieb John Larkin:
I still have my HP-35. It still worked last time I checked it.
But now I use a work-alike on my android cell phone. Less things to carry with me.
Gerhard
I had a pal with one of those.
Socking great V-twin at the front, one wheel at the back, 2-speed transmission using chains (fast and ridiculous), steering about three quarters of a turn full lock to full lock.
Starting, you first had to set the hand throttle, and retard the spark, then stick the handle in a hole halfway down the chassis, lift the decompressor and wind like crazy, while the chassis flexed and groaned. Dropping the decompressor gave you a loud bang, and the muffler clattered across the street.
Having finally got it going, he would beat a hasty retreat with the muffler on the passenger seat, before the neighbors lynched him.
He claimed it was good for 100MPH. AFAIK, he's still alive.
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
Hmmm, I guess it wasn't weighed down by useless stuff, like transmissions and differentials and seat belts and girlfriends.
-- 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
It wasn't weighed down by much at all. Two people could lift the tail, and wheel it like a wheelbarrow.
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
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