Old-fart electronics quiz

[John Woodgate]

I read in sci.electronics.design that Ben Bradley <ben_nospam_bradley@mi
ndspring.example.com> wrote (in <av8o001q3nvddetveeda0rsendvogf6r26@4ax.
com>) about 'Old-fart electronics quiz', on Mon, 19 Jan 2004:

God named the colors after the initials in the name of an early
admirer of the rainbow, Roy G. Biv: Red, Orange, Yellow, Green, Blue,
Indigo, Violet.

These days we don't distinguish 'indigo' from all the other shades of
blue. In Newton's day, the number of shades of blue dyes and inks was
much smaller, and 'indigo' was distinctly different.

 

[John Woodgate]

I read in sci.electronics.design that Roger Johansson <[email protected]>

Socialism became very popular among the people of Europe.
One big country, Russia, had already fallen, and several other countries
were coming after, the capitalists just had to do something or see their
system fall for the will of the people in democratic elections.

You mean 'in the last democratic election for over 70 years'.

 

[John Woodgate]

I read in sci.electronics.design that Precious Pup

True. It is stupid because it is poor technique. That's why it died a long
time ago. Read Radiotron.

I read it before you were born, puppy.

 

[John Larkin]

I put this line into google:
Hitler "Henry Ford"
and found some very interesting historical material already in the first
few links.


Socialism became very popular among the people of Europe.
One big country, Russia, had already fallen, and several other countries
were coming after, the capitalists just had to do something or see their
system fall for the will of the people in democratic elections.

Did you consider Soviet communism to be responsive to "the will of the
people in democratic elections"?

We could have abolished the money system and let everybody do whatever they
liked. Voluntary work had been enough to satisfy all material needs.

After about 95% of the population died off from hunger and disease.

John

 

[Jim Weir]

Then there was the cow that drank a quart of ink and mooed indigo.

Jim


John Woodgate <[email protected]>
shared these priceless pearls of wisdom:


->These days we don't distinguish 'indigo' from all the other shades of
->blue. In Newton's day, the number of shades of blue dyes and inks was
->much smaller, and 'indigo' was distinctly different.

 

[John Larkin]

True. It is stupid because it is poor technique. That's why it died a long
time ago. Read Radiotron.

It made sense when tubes and batteries were dominant as regards
original and replacement cost. A tube used to cost a few week's pay
for a lot of people ca 1925, and it'd be doing good to last 1000
hours.

Nowadays, an installed resistor or a capacitor can cost a hundred
times the price of an integrated transistor, so circuit topologies
naturally shift.

John

 

[Jan Panteltje]

Oh, don't start me off on the great days of Tottenham Court Road! It's
too sad to think about how all those wonderful outlets have just
turned into 'latest must-have electronic gadget' shops. Not a single
discrete component to be found anywhere. Mail order and Maplin are the
only alternatives now. :-(

Guess I am lucky here in the Netherlands, 3 shops with 15 minutes drive
of where I live, 2 in the same street next to each other...
They are so friendly, especially if you say, oh, well if you don't have it
maybe next doors ;-)
They will find it, no matter what it takes.

 

[Jan Panteltje]

I read in sci.electronics.design that Allan Herriman <allan.herriman.hat
[email protected]> wrote (in <fkpm00l1a68r0hi2lpocj3fbf7ut6btr
[email protected]>) about 'Old-fart electronics quiz', on Mon, 19 Jan 2004:
First, silver is 10% tolerance, not 20%. Second, yes, when 10% tolerance
parts were in use, you could get E24 values if you ordered a minimum
quantity.

John, regarding that 450 kHz, it keeps bugging me, some years ago
I was in the UK and ordered some IF filters, I just got one from the box (to make
sure I remembered that right), I ordered the Murata? 455 kHz mechanical ones
(have no RS catalog here so no number I can supply), these are the ones with
10kHz bandwidth.
I had a choice of bandwidth, but not sure I had a choice of 455 versus 450 kHz.
Did you really mean to say that radios in the UK use 450kHz ? That for sure would
require import stuff, manufacturers of 'alien' radios would have to make special
versions?
These mechanical ones are very cool IF filters B.T.W. and fixed, so no
adjustment, good out of band rejection.
Would you like to expand on that 450 kHz? sort of curious.
JP

 

[Jan Panteltje]

On a sunny day (Sat, 17 Jan 2004 13:06:58 -0800) it happened "Max Hauser"
[snip]

6. What is a class-C amplifier and where is it typically used?

Amp biased so it is conducting less the 180 degrees, use RF amp.

Specifically, an RF amp best used for constant envelope modulation,
e.g. CW, FM.

[snip]

2.4 MegOhm, 20 %, are you sure ;-)?

Do you mean that this is not feasible? 2.4 is an E24 value (with
about 10% spacing between values ... 2.0, 2.2, 2.4, 2.7, etc.), and I
understand these are not made in 20% tolerance. Well, there's no
point in doing it, but there's sure to be a manufacturer somewhere ...

Regards,
Allan.

Yes it is 10% I was wrong about that.
2.4 seemed stange to me, hard to get that range here.

 

[Paul Burridge]

I used to have Varilux lenses, but the eyes were getting so bad that I
had to return to tri-focals.
Cripes!

Fifteen years ago I opted for RK, not realizing that weakens the eye
and you gradually go far-sighted.
RK?

Last year I did the lens replacement bit (AKA cataract surgery)...
works like a champ. I only need readers for close stuff, and don't
generally need them at the tube (NEC XE21).

cataracts and lenses are different things, Jim. However, I did once
know a guy who'd had a *lens* replaced with an artificial one which
had a weird blue-ish tint in certain lights. Creepy. Quite
appropriate, though, since he had a murder conviction and had spent
very many years in prison for it!

 

[Richard Owlett]

I read in sci.electronics.design that Jim Thomas <[email protected]>



But who wants a 234567800 Mohm resistor?

IIRC we used resistors of similar magnitude for the electrometer in
the Isotope Ratio mass spec I had to maintain. Yep, a finger print in
wrong spot was a *DEAD* short.]
( we did prefer 1 followed by lots of zero's ;}

 

[Jerry Avins]

These resistor were manufactured and tested in accordance with MIL-STD
which provides for permanent resistance change of carbon composition due
to environmental overstress factors such as temperature, voltage, and
power dissipation extremes. So it would not be unusual for the initial
tolerance of a component with no stress history to be much better than
allowed by the rating- it is in fact a manufacturing necessity.

Sure. (That yellow band and all that.) What I intended to convey and
what you emphasize is that selecting those that don't meet spec to sell
at a looser tolerance is not a reasonable way to dispose of bad product
unless your reject rate is anyway very low. It worked for a while with
discrete diodes and transistors, and still does with guaranteed speed of
processors, but it almost never the case with mature products. (I made
some of my band-edge resistors by running two watts into a quarter-watt
resistor for what I judged to be the right time. Sometimes it worked.)

Jerry

 

[Jerry Avins]

I read in sci.electronics.design that Allan Herriman <allan.herriman.hat
[email protected]> wrote (in <fkpm00l1a68r0hi2lpocj3fbf7ut6btr
[email protected]>) about 'Old-fart electronics quiz', on Mon, 19 Jan 2004:

On Sun, 18 Jan 2004 01:11:35 GMT, Jan Panteltje


On a sunny day (Sat, 17 Jan 2004 13:06:58 -0800) it happened "Max Hauser"
[snip]

20. What does it mean when a resistor is marked with bands
red-yellow-green-silver? A capacitor with "104K?"

2.4 MegOhm, 20 %, are you sure ;-)?

Do you mean that this is not feasible? 2.4 is an E24 value (with
about 10% spacing between values ... 2.0, 2.2, 2.4, 2.7, etc.), and I
understand these are not made in 20% tolerance. Well, there's no
point in doing it, but there's sure to be a manufacturer somewhere ...

First, silver is 10% tolerance, not 20%. Second, yes, when 10% tolerance
parts were in use, you could get E24 values if you ordered a minimum
quantity.

John, regarding that 450 kHz, it keeps bugging me, some years ago
I was in the UK and ordered some IF filters, I just got one from the box (to make
sure I remembered that right), I ordered the Murata? 455 kHz mechanical ones
(have no RS catalog here so no number I can supply), these are the ones with
10kHz bandwidth.
I had a choice of bandwidth, but not sure I had a choice of 455 versus 450 kHz.
Did you really mean to say that radios in the UK use 450kHz ? That for sure would
require import stuff, manufacturers of 'alien' radios would have to make special
versions?
These mechanical ones are very cool IF filters B.T.W. and fixed, so no
adjustment, good out of band rejection.
Would you like to expand on that 450 kHz? sort of curious.
JP

Most or the IFs in the "All-American Five" circuit ran at 455 KHz, and
my old Stromberg-Carlson console superhet was tuned to 456. By the time
a radio was realigned in a shop with typical service-shop equipment, the
actual IF frequency was anybody's guess.

Jerry

 

[Richard Owlett]

On a sunny day (Sat, 17 Jan 2004 13:06:58 -0800) it happened "Max Hauser"

[snip]

6. What is a class-C amplifier and where is it typically used?

Amp biased so it is conducting less the 180 degrees, use RF amp.

Specifically, an RF amp best used for constant envelope modulation,
e.g. CW, FM.

HUH???
Seems to me the typical AM transmitter of the 60's was a plate
modulated class C amp ;}
[ Now if you wanted to AMPLIFY an AM signal, then you went Class A or
AB ( can't remember spec of Class B -- must be getting old ]

 

[Jerry Avins]

Jan Panteltje wrote:

...

2.4 seemed stange to me, hard to get that range here.

One decade of standard values for 5 and 10% (with *) resistors is

10*
11
12*
13
15*
16
18*
20
22*
24
27*
30
33*
36
39*
42
47*
51
56*
62
68*
75
82*
91

There are twelve 10% values and 24 at 5% in about as good an exponential
sequence as can be had with two-digit integers. The values are are about
twice as far apart as the tolerance, so that ideally, there are no gaps
and no overlaps.

Jerry

 

[Jerry Avins]

Mark Fergerson wrote:

...

I just take my glasses _off_ to read them. I've been hoping for
presbyopia, but no dice.

Mark L. Fergerson

As far as I know, a forlorn hope from the start. Presbyopia doesn't make
one far sighted, it just fixes the lens's focal distance at whatever had
been its farthest.

Jerry

 

[Jim Thompson]

cataracts and lenses are different things, Jim. However, I did once
know a guy who'd had a *lens* replaced with an artificial one which
had a weird blue-ish tint in certain lights. Creepy. Quite
appropriate, though, since he had a murder conviction and had spent
very many years in prison for it!

Neeerp! The game here in the colonies is to simply drop a new lens in
to cure cataracts. I didn't have cataracts, just needed the
refocusing ;-)

...Jim Thompson

 

[Jerry Avins]

I read in sci.electronics.design that Mark Fergerson <[email protected]>
wrote (in <[email protected]>) about 'Old-fart electronics
quiz', on Mon, 19 Jan 2004:




Enjoy it. Vestigial accommodation is not too much fun, when you need to
see the PCB at 60 mm, the scope screen at 60 cm and the view out of the
window at 60 m. I can use Varilux lenses, but some people find they
can't use them.

I can use them, but I won't. My bifocals are essentially reading glasses
with peepholes at the top. (Executive bifocals with the division just
under the pupil when looking straight ahead) There is not the usual
prism to assist convergence, and so no lateral displacement in the
center of the field when shifting between lenses. With them, I can climb
rocky paths with sure footing and disassemble a watch. What I lose with
varilux is the ability to distinguish 15/64, quarter inch, and 17/64 on
sight. But seeing the difference between 8 mm and 5/16" is beyond me, so
I need a micrometer anyway. :*)

Jerry

 

[JeffM]

4. Who developed the op amp, and when?

maybe. he did develope the feedback amp for sure. It was the
feedforward amp prior to that, but at the time, ou couldn't get
good tubes cheap enough to make the feedforward amp work right.
Active8

I always thought that Black's work was on paper only.
(Didn't have good enough hardware available
--kinda like the guys who though up FETs,
but didn't have adequate process technology.)

Earliest reference I know of:
Loebe Julie 1942
http://www.elecdesign.com/Articles/Print.cfm?ArticleID=2530 (Bob Pease)

 

[Roger Johansson]

Did you consider Soviet communism to be responsive to "the will of the
people in democratic elections"?

About as responsive as the american capitalism was responsive to communism.

Remember that the two systems were in a war, cold or hot, with each other.
The intensity of the propaganda was very high.
The anti-communism in USA was in no way less intensive than the
anti-capitalist propaganda in Russia.

Mc-Carthy-ism and a hunt on communists in USA was very intensive, as was
the hunt for traitors in the leadership of Soviet under Stalin.

But the most important fact is that capitalism was the old system which
defended itself against new political views which put the people in power
instead of the rule of a few rich guys.

It was USA that fought communism, and forced Soviet to build weapons to
defend itself.
Soviet had no need for dominating the world by violence, it had the
sympathies of millions of workers around the world.

All through the 20th century it has mainly been the capitalist side which
has needed weapons and violence to crush the will of workers around the
world.

USA has financed hundreds of violent dictators and arranged hundreds of
coupe d'etats around the world to keep the power.

Think of Chile, for example, where the people voted for a socialist
president, and USA financed a general to use violence to take the power, so
the american interests in the country could be defended.
So they could continue to have the copper to a very low price.