Using Spice to verify a circuit works

Railed is pretty nonlinear.

Sure will. It's a "class C" oscillator.

It oscillates, so it's an oscillator.

Actually, I think I've seen some circuits that do exactly that. Except they were biased so they start linearly, then go into hard limiting.

I don't see how you can get enough swing out of the tank to keep it running. Got an example?

No, it's a ringdown circuit. It is also not self-starting.

An extended version of Mann's hockey stick :-)

Lots of averaging of proxies, some of which are calibrated years some are not. If there are decades or even centuries uncertainty about dating of events, the same events will have peaks at different times in different series, thus averaged out. Then one proxy only (temperature measurement at 2 m height) id appended to the end of the graph.

Different proxies are given different weights i.e. a single available proxy from a continent is given a large weight to represent that continent.

Look for example at

Some old proxies show as steep changes in temperatures as the 2 m measurement proxy.

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else can you support an answer

If you

oys are still collecting.

global climate because they happen over a few year.

face currents but the return currents flowing in the depths of the oceans a re less easily observed (which is why the Argo Buoy observations were set u nder way).

It might. We don't know what the deep ocean currents are doing now, and we know even less about what they were doing from 9000 to 5000 years ago

The ice mostly melted after it had slid off into the oceans, so the heat in volved came from cooling the oceans, rather than cooling the atmosphere.

The sea level rise started about 19,000 years ago and finished about 6000 y ears ago. That period includes the Younger Dryas

That took place 12,900 to c. 11,700 years before present (aka 1950)and was driven by a very visible ocean current change - the Gulf Stream stopped flo wing.

Your 9000 to 6000 years ago might just be the ocean circulations getting ba ck to "normal". One of the side effects of the Younger Dryas was that the s outhern oceans got the benefit of the heat that normally goes north in the gulf stream, and they might have taken a few thousand years to cool back do wn to normal.

The sort of hindcasts that John Larkin gets spoon fed on denialist web-sites might do that.

How would he know them when he only reads parodies of what they write on denialists web-sites.

So why isn't the fossil carbon extraction industry fabricating the kind of short terms simualtions that would sell their massive political intervention?

Nobody is saying that. AOC claimed that a dim millenial might say that, which isn't any kind of prediction, but John Larkin can't think clearly enough to understand waht she was actually saying.

It hasn't happened yet, or at least not to a devasting degree. Australia has had to cope with more frequent droughts in recent years, and several places have had to cope with unusually intense cyclones (which do flood cities).

The simulations model climate, not weather.

And your example of such a simulation is?

Climate simulation is an academic activity. Academics get more money by impressing other academics, not politicians.

Actually, climate modellers do. There's a planet's worth of real climate out there.

But he did popularise good science. The profits were incidental, and came a long time after "Earth in the Balance" got published back in 1992.

Which simulations are those. Link please.

AOC was inventing something a dim millenial would say. It wasn't any kind of prediction.

The simulations have been pretty bad so far.

Probably false, but 'pretty bad ' is vague, so that's an untestable assertion.

Do you ever read the labels? That's a bunch of underspecified averages; I'm not sure why 'troposphere' (low-altitude air) needs satellite data, that's NOT the best source. Why is balloon data so prominent? It isn't a big data set, and one doesn't launch balloons in all weathers.

With human sources being involved, why does prediction spanning 45 years get a prominent mention? There's not been 45 years of constant and unchanging human sources, after all.

There's no indictment of any particular property of any particular simulation (and one of the small-character 'simulations' graphs DOES match the 'observations' graph pretty well, though we cannot tell which).

The person responsible for the graph, John Christy, has political friends and has secured official appointments and Congressional hearings, but is not widely regarded as informative by his fellows. His 'Alabama state climatologist' position looks to me like a sinecure.

That's a good example that Spice can't handle (well, not correctly); the initial condition for a Schmitt trigger (or '555, or hysteretic gate) with the right feedback is indeterminate (depends on tiny amounts of noise or capacitor charge).

There is nothing wrong with the HC14 in SPICE. It runs fine.

Whatever the initial conditions, the feedback will drive the input voltage to the opposite side of the hysteresis voltage. It cannot fail to start.

Try it:

Version 4 SHEET 1 1028 680 WIRE 112 256 80 256 WIRE 144 256 112 256 WIRE 256 256 240 256 WIRE 288 256 256 256 WIRE 256 288 256 256 WIRE 80 384 80 256 WIRE 256 384 256 368 WIRE 256 384 80 384 WIRE 80 400 80 384 WIRE 80 480 80 464 FLAG 80 480 0 FLAG 288 256 U1O FLAG 112 256 U1I SYMBOL res 240 272 R0 SYMATTR InstName R2 SYMATTR Value 10k SYMBOL cap 96 464 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 8 Left 2 SYMATTR InstName C1 SYMATTR Value 1n SYMBOL 74hc14 192 208 R0 SYMATTR InstName U1 TEXT 80 48 Left 2 !.tran 0 40u 0 TEXT 432 48 Left 2 !.inc 74hc.lib TEXT 432 72 Left 2 !.options plotwinsize=0 TEXT 432 96 Left 2 !.ic V(U1I)=0 TEXT 80 16 Left 2 ;'74HC14 Astable Multivibrator

If you don't have 74hc.lib you can get it from Helmut's site.

LT Spice will sim a Schmitt gate oscillator fine, if you set up the gate params right.

On a sunny day (Sun, 23 Jun 2019 21:57:05 -0700 (PDT)) it happened whit3rd wrote in :

In reality, apart from all the 'noise', a power up sequence will cause enough signal to start oscillation?

There are cases in which an oscillator starts fine when battery powered, but not when powered from the mains.

In a mains power supply with big electrolytic capacitors it can take a long time, before the capacitors are charged, thus the dV/dt is too slow to kick start the oscillator. When battery is used, the voltage grows immediately, having a much higher dV/dt, which will give a nice kick.

What do you need to do for gate params?

They were retired from active service in 2010 and then I think sold to the US for spares the following year.

UK test pilots are quite impressed with the ease of flying the F-35:

At present we just have a big new aircraft carrier with no aircraft!

John Christy is a climate change denier.

It took years before the rest of the field could persuade Spencer and Christy that their satellite data wasn't being properly corrected.

sus-97-per-cent/2017/may/11/more-errors-identified-in-contrarian-climate-scientists-temperature-estimates

John Larkin hasn't noticed this, which is odd because it is pointed out to him from time to time.

Harrier was cool, but it is subsonic and has a gigantic radar cross-section. It's over 50 years old.