Vintage equipment voltage measurement

ttainment

A rather implausible claim, unsupported by any shred of statistical evidenc e. One has to suspect that you are another Daily telegraph reader who credo ulsy soaks up tales of gloom and doom.

n subjects such as media science and equally useless subject that have few opportunities. As a result many do go onto flipping burgers.

It's not the subjects studied that are useless, but rather the people who s tudy them. I've met some perfectly useless (or at best minimally useful) pe ople who seemed to have a good degree in electrical engineering (which also happens to be the subject that Rowan Atkinson got his degrees in, not that any of this study seems to have been of any use to him).

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Living rent-free with your parents is cheap.

Read the book. Didn't bother to see the film, but the media hype did make i t easy for me to replace my worn-out copy of MTAFC.

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Bill Sloman, Sydney
Reply to
bill.sloman
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You make none of them work? It's rather difficult to stay in business with a batting average of zero.

Notice that I said "usually". Long ago, I worked for a repair shop that did warranty work for the local tape recorder and cheap audio importers. Making 100+ work was what I was doing. I'll give their factories in Japan credit for being very consistent. When one tape recorder had a manufacturing problem, it was highly likely that all of them had the same exact problem. I could look at their inspection stickers, see who did the work, sort the machines by inspection sticker, and every one of the machines would have exactly the same problem. Doing that almost made it profitable to do flat rate warranty work, which was normally a loss leader in order to get the more lucrative out of warranty repairs.

However, that was the exception. When I was designing marine radios, I had great difficulties teaching the difference between an engineering tech and a repair tech. The repair techs usually considered it perfectly acceptable to take a prototype run of 10 radios, and "fix" them 10 different ways. It took a bit of effort to convince them that was a bad idea and that in a production environment, all the radios should be exactly the same with no creative substitutions, customization, or selected parts.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

Out of curiosity, how did you match the monikers?

Reply to
Tom Gardner

if too high add parallell resistance. if too low select a higer voltage range.

unreal 5uA full scale.

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     ?
Reply to
Jasen Betts

In the US, the skools seem to teach kids how to be better consumers. What bothers me is not that high skool graduates don't know how to do anything useful, but rather that they don't want to learn anything new and that the push towards excellence has been replaced by glorified mediocrity, where everyone is expected to be "equal". Most of that is a side effect of "mainstreaming", which like all such programs, has good and bad points plus the usual unanticipated side effects.

Is the Daily Mail leftist, centrist, or rightist? Since Mr Doom seems to be more to the left, I suggest that he read his news from sources that are as far to the right as his digestive tract can manage. If his leftist convictions are still intact after a few months of that, then he is a true believer.

One must do something with all the "Classical Education" graduates.

The only reason I attended college was because the US was busy fighting a war in Viet Nam at the time and I was in danger of getting drafted into the army. Also, my parents agreed to subsidize my education. Otherwise, I would probably have gone directly to work or started a small business after 2 years of college (Junior College as it was called at the time).

College graduates working in fast food preparation isn't much of a disgrace. One of my many jobs during early college was manager at a local 24hr coffee shop. The prime purpose of the restaurant was to launder money from illicit operations for the local criminal organizations. Not quite flipping burgers, but close enough. Later, my perfect timing had me graduating college directly into a small recession, where the aerospace industry was in the process of collapsing due to the cancellation of the space race. The best I could do was find a job fixing CB radios and installing radios in cement mixers (because all the burger flipping jobs were taken). Like all such diversions, the job was only temporary. As the economy recovered, so did I.

Assembling hamburgers is not really cooking. Somewhere along the line, I forgot to learn how to cook. Every attempt was a failure because I don't read the instructions and wouldn't follow the instructions anyway. I'm just too creative and never do anything twice the same way twice. In the few jobs and tasks that require creativity, ingenuity, and logical thinking, such attributes are useful. For most everything else, it's potentially dangerous and a great way to get fired, which is why I'm self-employed.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

And if the ex Secretary of State for Education (and poisonous brexiteer) Michael Gove got his way, they won't be taught to think at all, only to regurgitate "useful" facts such as when King Henry II reigned. But then he also wanted more madrassahs, under the guise of wanting more religion in education. He even approved the creation of three Creationist schools.

But of course the success and failure is far more nuanced than CD states.

Old farts have always said that, and always will.

When doing A-level pure maths, homework often consisted of doing questions from past exams. The older ones were more difficult than the recent ones, with those from the early 50s being bloody hard.

Reply to
Tom Gardner

In the old analog meters, there basically was only a current meter, often 50uA full scale, and when measuring voltage a suitable series resistor is switched in to make it draw 50uA at the full scale reading.

So a 10V range would have a total resistance of 10V/50uA = 200k (which would be the resistance of the meter itself plus the series R). At 10V measured voltage there is 50uA through the 200k resistance.

When looking at this, any range will have a resistance of 1V/50uA per volt of range, hence "20K per volt". The 100V range will be 2M.

This is no longer true for a modern DVM. They usually have a 10M series resistor on the input with selectable resistors to ground to make a voltage divider that outputs the desired voltage for the ADC.

So, depending on the range you select, the input resistance will be

10M plus a small value that will get smaller when you select a higher range.

Therefore there is no fixed "K per volt" input resistance anymore, and selecting a higher range will not result in a higher resistance.

However, as already can be seen, the "20K per volt" is not really telling the input resistance to be used in the measurement. It depends on the selected range, and available ranges vary between meters. One may have ranges of 10-30-100 and another maybe 10-50-200. When you need to measure a 24V testpoint, on one meter it may be on the 30V range (and thus 600k resistance) and on another meter it would be the 50V range (and thus 1M resistance). It is expected that the person doing the measurement understands how this could affect the result, if it does at all. (when measuring a supply voltage, there should not be a noticable difference. when measuring in a high-impedance signal circuit, there could be)

Reply to
Rob

There is, of course, one domain where that engineer/technician distinction is almost completely meaningless: software, particularly "enterprise" software.

Worse, they are proud of it, and actively seek to merge all development phases. The end result is that many sticky fingers poke at the various parts of the system, and eventually nobody knows a system's specification or what it actually does.

Provided it doesn't fail the tests, it is defined as working.

Reply to
Tom Gardner

When I was in grade school I was taught that etc. is pronounced 'and so forth'. Yes, that is what the teacher told us to say when we saw it. I never thought it was correct, but what can you say when the teacher says it?

Bill

Reply to
Bill Gill

I was taught that 'viz' (from Latin videlicet) is pronounced 'namely'.

Cheers

--
Clive
Reply to
Clive Arthur

with a batting average of zero. "

No you sarcastic non-pork eating MF. LOL I made many things work with no se rvice info, and not even good part numbers on the frikken transistors n shi t, even without markings on resistors. Even without silkscreen on the board , and components with like 5 wires, some kind of bandpass filter with no go od numbers on it.

There are only so many ways it CAN work, so it MUST work one of those ways. Now to find out.

That thinking kept me pretty close to batting 1,000. Close enough that I co uld write my own ticket.

Reply to
jurb6006

disgrace."

No honest work is a disgrace.

local 24hr coffee shop."

I saw a sign at a local grocery that said they were hiring a general manger for $ 20.25 an hour. There is definitely no disgrace in that kind of money , I mean you can almost live on it.

launder money from illicit operations for the local criminal organizations."

And you get your tickets fixed.

my perfect timing had me graduating college directly into a small recession, where the aerospace industry was in the process of collapsing due to the cancellation of the space race."

Actually that was an extension of the cold war scam. See, none of these ric h MFs who have it made for life and for the next few generations of their f amily want to upset the apple cart. They don't WANT to blow off a nuke. The scam of the red menace and the decadent Americans all was all a ruse to ge t popular support for a military buildup which resulted in the co-conspirat ors of the scam becoming the 2 preeminent super powers in the world.

It can be.

as a failure because I don't read the instructions and wouldn't follow the instructions anyway."

You didn't "feel" it. Once you get that "feel" you need only occasional ins truction, there are places ion the net to get it. But if you don't have tha t "feel" you are doomed to follow directions.

Me too kinda, but I can't call this being in business.

Reply to
jurb6006

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