J
Jim Thompson
Varicap parametric bridges.
John
What did they call the big-ass ones.
I vaguely remember using some kind of varactor to triple me up to the
2 meter band. (5W
...Jim Thompson
Varicap parametric bridges.
John
Is that term in the Dictionary of Electronics?
Bill? Did I miss an actual technical contribution by Sloman ?![]()
I love auto-zeroing.
Once upon a time, I even built a micro-voltmeter, using LM324's, to
measure voltage drop on PCB tracks, to locate shorts.
Zero, measure, zero, measure....
What did they call the big-ass ones.
I vaguely remember using some kind of varactor to triple me up to the
2 meter band. (5W
...Jim Thompson
You're showing your age, John. And they weren't all that wonderful...
CMOS is MUCH better.
Paramps are cool. Somebody did a paper on using ceramics caps as
active gain elements, and I have a paper on making nonlinear
transmission lines (shock lines) using the nonlinearity of ceramic
caps.
Just because I know about this stuff doesn't mean I'm old enough to
have experienced it all first-hand.
John
Hello Jim,
Or maybe he is too young. In my days choppers were those motorcycles
with extremely long handle bars, where the front wheel was way out there
and you wore a bandana and some cool tattoos. Oh, and it had to be loud.
Regards, Joerg
Hello Jim,
Or maybe he is too young. In my days choppers were those motorcycles
with extremely long handle bars, where the front wheel was way out there
and you wore a bandana and some cool tattoos. Oh, and it had to be loud.
Winfield said:Pooh Bear wrote...
If you wish, but it'd be better to discuss your application and
circuit, to see why you need 0.1mV, and if there's a workaround
that'll allow you to use cheaper opamps.
Winfield said:Spehro Pefhany wrote...
TI's OP07DD, 60uV typ, 32.5 cents qty 2500, not bad, good call Spef!
Rock said:AD8551, prob. overkill for your application, 1uV offset, sold as a zero
drift op amp. Just used these as a thermopile amplifier, they are
simply amazing. At $2.30 in singles from Digi Key they are a wonder!
Joerg said:Hello Graham,
If you can afford to do auto-zero as Bill suggested and your opamp
budget really is 15 cents for a dual: Why not use ye olde LM324 and
clamp to zero? Ok, you'd have to spring another 5c or so for a BSS123 to
do the clamping but a quad LM324 can be had for around 10c.
Jim said:Reminds me when we first met the daughter-in-law's family.
My son, bride-to-be and her mother show up in the bride's Honda Civic.
They say that father is on the way.
All of a sudden the house is shaking, and this crazy, hippy-looking
guy, with a bandanna, comes up the hill on a Harley chopper... so loud
that all the neighbors pour out of their houses.
It's the father-of-the-bride. Turns out he's a big-time dealer in
Harley parts in LA (now moved to Palm Springs).
Then he took off the bandanna... it had a velcro closure. I gave him
a ration of shit for lack of authenticity ;-)
Jim Thompson said:Bill? Did I miss an actual technical contribution by Sloman ?![]()
I love auto-zeroing.
Once upon a time, I even built a micro-voltmeter, using LM324's, to
measure voltage drop on PCB tracks, to locate shorts.
Zero, measure, zero, measure....
Jim Thompson wrote...
Haven't we all? Win has got a couple of pages on lock-in detection
in "The Art of Electronics" - it isn't exactly rocket science.
Certainly best bet so far. I'd forgotten it. I'm sure I used one about 20 yrs
ago as a photodiode amplifier.
Graham
John Larkin said:Burr-Brown did a very impressive potted-brick opamp using modulated
varicaps in the front end; CMRR was about infinite, as the entire
input circuit was transformer-coupled. I think Bob Pease did an
article on it. I seem to recall that TI did a monolithic varicap opamp
at some point... I may have a datasheet in The Dungeon.
Paramps are cool. Somebody did a paper on using ceramics caps as
active gain elements, and I have a paper on making nonlinear
transmission lines (shock lines) using the nonlinearity of ceramic
caps.
Just because I know about this stuff doesn't mean I'm old enough to
have experienced it all first-hand.
Bill Sloman wrote...
We introduce the auto-zero circuit as well, pg 392.