Craig Sawyers

You'd make a killing selling those in China

Apparently this is a lifesaver. So your ship goes down or plane crashes the sea. You get into the bubble rather than using a buoyancy aid. Oddly I kind of get this - it is common to put something similar to that in the bottom of your pack when walking in the wilderness. When the weather turns nasty you pull the thing out and get into it (personal versions and larger ones for up to ten). The idea is to keep the wind and water/snow off you, and are essential in case of injury.. I have both. They pack really small. They are brightly coloured so emergency rescue can find you. Similar problem in the water - the bubble would go a long way to prevent hypothermia. Some of the other ones above - I have absolutely no idea at all!

A few patent landmarks

I like that this guy is still alive. I have no idea how or why that should be the case.

Took me a while to understand the perspective, then I realised that it was a view from the *top* of Raven Crag looking roughly North down Thirlmere (note - not Lake Thirlmere, because a mere is a lake. So it is simply Thirlmere. Pedantic mode = off). So on the left are the slopes of the Helvellyn range. In the left middle distance is Seat Sandal (and above it the shoulder of if Stone Arthur and Great Rigg. And facing Seat Sandal on the right (with the concave shape) is Steel Fell. In the gap between the two is a low pass called Dunmail Raise (Dunmail was an local chieftan). Just to the right of the view point is Bleaberry Fell and High Seat. In the far distance you can see Loughrigg Fell - the subject of another of Knuck's postings. Incidentally, it is one of those trick questions - how many Lakes are in the Lake District? Answer - one. Bassenthwaite Lake. All the remaining fifteen bodies of water in the Lake District are Meres, Waters and Tarns.

Apparently "In the United States, the record reached #61 on the Cash Box Top 100 Singles. The single also peaked at #70 on the Billboard Hot 100 that May". So it was never a blockbuster in the US, but did OK.

Bit of a one-hit guy - but what a hit! RIP Peter Sarstedt. Too young at 75. That single song was a real part of my youth.

Liked the image from Loughrigg (pronounced Luff-rigg) Fell, a small (1000 foot) but worthwhile hill above the town of Ambleside, Been up several times. Currently been up 74 of the Lakeland fells over the years to October 2016.

Happy birthday Jacob - good to see you back.

Happy birthday!

Oh bloody hell. Mother and daughter in a few days. RIP Debbie Reynolds. I went through an on-line photo album of those that we have lost in 2016, because of the sheer number who have gone you lose track - and it is a roll-call of the great and the good. Quite a depressing year in that regard.

Regarding battery, our daughter had precisely the same problem in her Ford Fiesta. Fine for a week or two, then totally dead until started on cables. Fine for a week or two - repeat as necessary. Turned out to be the battery. Apparently modern batteries can do this, caused by an intermittent short (or open) circuit inside. The dead one was the original battery, fitted when the car was new.

Jeeze - Carrie Fisher. Same age as me - and oh boy is that a sobering thought. RIP Carrie

My son just now said "What the fuck - George Michael just died aged 53. This damned year just decided to pack a few more in". Suspected heart failure. RIP George Michael

It just seems to keep on coming this year. RIP Ric Parfitt, again far too young at 68.

Happy birthday! You're in illustrious company - 25th December was Isaac Newton's birthday too

But, but - they are upside down! The bases will come out with the wrong phase

Aged 66. Too damned young. RIP Frank Murray.

Have a great one!

I completely agree that a chip, or hybrid solution would be best. In fact the concept of using a laser trimmed metal foil R2R network, where the foil network was layed down by photolith ought to be superb, hermetically sealed and dry nitrogen filled. Cheap it would not be...

Unless my use of Google is in meltdown, the PCM1704 is obsolete. Is this wrong? For discrete R2R, assuming that matching is done correctly, the whole resistor chain needs to be kept isothermal. There is little evidence that this is the case, but could be arranged to be the case.

There is absolutely nothing to prevent laser trimming, or selection to any tolerance you like provided that temperature and voltage coefficients are low enough. 0.01% tolerance is 10ppm or 1 ohm error in 10k. Temperature coefficient is around 3ppm/C so to match tolerances at a 10ppm level the measurement temperature has to be constant to 1C or thereabout. Foil resistors are superb, but are punishingly expensive. And any SM component has to be soldered using precisely the soldering profile in the datasheet for the parts - because component stress and thermal shock will shift the resistance too. However you look at it, it isn't trivial, is all I am saying.

It is all down to how the tolerance is statistically distributed. You can get two different scenarios. (i) All resistors in any production batch are clustered in value or (ii) resistance values in a batch are randomly distributed. This could only be established by measurement. However, if (i) holds then the batch will have a constant error and if (ii) holds then the values will be normally distributed. Typically the nominal tolerance will be 3-sigma, which would mean that less than 0.27% of resistors were out of tolerance. So the majority of resistors will be significantly better than nominal tolerance. The difficulty in getting accuracy is that you need to test a large number of resistors. If 100 resistors are tested the nominal error is 10%. To get 1% confidence you would need to test 10,000 resistors - er, no thanks at that level!

You always crack me up

I see your fat German and up you a skinny geriatric Brit - the impeccable Ginger Baker, superbly recorded in 2005 in an 8 minute solo: