Old-fart electronics quiz

[Paul Burridge]

I bought three of those OC71s in the early 1960's for a guinea,
my auntie who was a tayloress at that time earned four guineas
per week. Just for interest Paul, they were used in a
Super regen. RC receiver with a valve (XFY34) RF amplifier,
miniature little thing. 1.5V heaters and 22 volt main supply.
The valve cost me 15/6 from the Clyde model dockyard,
a hobby shop along Argyle street in Glasgow. The transistors
came from a disposal shop near "The Barras," an open air
market place similar to Pettycoat lane/Portobello road in
your area.

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. :-(

 

[Jim Thompson]

Jim,

Thanks for the entertaining post.

I'll be in Phoenix next month teaching
a DSP class. Maybe we can get together
and splash a few beers around.

[-Rick-]

[snip]

Sure. Just give me a call when you're in town.

...Jim Thompson

 

[Keith R. Williams]

Now days (at least at my job), most resistors are surface mount, so they have
numbers printed on them rather than color codes. And they're almost always 1%
tolerance.

They are harder to read without a magnifying glass, but easier to decode!

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.... and I thought it because I was getting to be an old fart. ;-)

 

[Jerry Avins]

John Woodgate wrote:

(snip)



The story that I used to hear was, at least at some time, the resistors
selected for the 5% batch came out of ones that would otherwise be the
10% batch. That is, the chance that a 10% resistor is within 5% of
its stated value is much less than the expected 50%.

That may not always have been true.

-- glen

That may have been true early on, but even in 1960, Allen-Bradley
composition resistors were usually within 2% of nominal, even with 10%
ratings. It was, in fact, very hard to find band-edge values. I kept a
set of specially marked ones for tolerance testing to be sure that my
circuits were robustly reproducible. I made many of those by starting
with a lower value and grinding into the carbon to raise the resistance.

Jerry

 

[Fred Bloggs]

That may have been true early on, but even in 1960, Allen-Bradley
composition resistors were usually within 2% of nominal, even with 10%
ratings. It was, in fact, very hard to find band-edge values. I kept a
set of specially marked ones for tolerance testing to be sure that my
circuits were robustly reproducible. I made many of those by starting
with a lower value and grinding into the carbon to raise the resistance.

Jerry

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.

 

[Jerry Avins]

American companies own the major part of the production capacity and
distribution nets of all video, movie, television production in the world.
They have dominated world media since 1945, including both entertainment
and news agencies.

They use sales tactics which force the buyers to buy whole package deals.
If they want a certain program they are forced to by a thousand other
programs too.

This situation means that any major tv channel is forced to cooperate with
the american-owned media companies and distribution nets.

Over the last 50 years this has resulted in a strong influence on most
countries of the american culture.

No one holds a gun to their heads. The consequences of not cooperating
are limited to economic ones, and those depend on the Swedish people
wanting what the big bad American corporations have to offer. Hollywood
may supply the drug, but it is consumed willingly by many. I don't have
TV cable; do you? (My country house has no TV at all. You can resist if
you choose to, but it's easier to blame someone else.)

Jerry

 

[Jerry Avins]

In my opinion this does nto justify the violence in US movies. Every product
in the world (including Heroine imported from Afghanistan and Guns exported
from the West) exists because it has a demand.

I agree with each of those sentences. Are they related?

Jerry

 

[Roger Johansson]

Hi,
Neutral, huh. You should be glad the
rude Americans were not neutral, or else your
parents skins would have ended up on
someone's lampshade.

It was the non-jewish capitalists, industrialists and bankers in USA,
Britain and western Europe who supported Hitler, Franco and Mussolini, and
helped them come to power, because they wanted to crush socialism and
communism in Europe and Russia.

If they had not supported these fascist dictators there would have been no
WW2, and there would have been no need for the russian army to save us from
fascism.

USA waited until the fascist armies were already beaten and they met very
little resistance when they took half of Europe to prevent the russian army
from taking all of it.

I agree with you regarding American television.

Thanks.

If the capitalist money and governments had not attacked and threatened
Russia and Soviet Union continually since 1917 and well into the 1970ies
the russians had not been forced to waste so much resources on building a
strong defence, and their communism could have developed in a less
authoritarian direction. They were forced to evolve into a centrally
controlled economy and to run the country like an army.

The whole history of the 20eth century in Europe was characterized by this
struggle between capitalism and socialism.

The radical socialists in Germany, Italy, Spain and elsewhere in Europe had
been voted to power by the people if these fascist dictators had not been
helped to the power by the capitalist side, and the history of Europe could
have been completely different.

 

[Jim Thomas]

Does anyone have any other non-component-value examples of the
color code being used?

God used part of it to encode the rainbow.

 

[Roger Johansson]

It was the non-jewish capitalists, industrialists and bankers in USA,

Britain and western Europe who supported Hitler, Franco and Mussolini, and
helped them come to power, because they wanted to crush socialism and
communism in Europe and Russia.

If they had not supported these fascist dictators there would have been no
WW2, and there would have been no need for the russian army to save us from
fascism.

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

The whole history of the 20eth century in Europe was characterized by this
struggle between capitalism and socialism.

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.

The radical socialists in Germany, Italy, Spain and elsewhere in Europe had
been voted to power by the people if these fascist dictators had not been
helped to the power by the capitalist side, and the history of Europe could
have been completely different.

If the capitalists had not found a way to stop the socialists we could have
seen a development in Europe and other parts of the world of an
anti-authoritarian socialism, where individual rights had been more
important than the collective, where production of food and other goods had
been more than enough for everybody.

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

 

[[email protected]]

|
|Bad
|Boys
|Rape
|Our
|Young
|Girls
|But
|Violet
|Gives
|Willingly

5% of the time for gold, 10% of the time for silver, and 20% of the
time for nothing at all.

Phil

 

[Al Clark]

God used part of it to encode the rainbow.

What saying did he use to memorize the sequence?

 

[Precious Pup]

I read in sci.electronics.design that Precious Pup


It's not stupid just because it's an old technique.

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

 

[Ben Bradley]

What saying did he use to memorize the sequence?

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.

 

[Jim Thompson]

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

I think it's wrong to call it "poor technique". It was cost-driven
engineering appropriate for the times (around and after the
depression).

BTW it was generally only IF and BB.

...Jim Thompson

 

[glen herrmannsfeldt]

glen herrmannsfeldt wrote:
(snip)


That may have been true early on, but even in 1960, Allen-Bradley
composition resistors were usually within 2% of nominal, even with 10%
ratings. It was, in fact, very hard to find band-edge values. I kept a
set of specially marked ones for tolerance testing to be sure that my
circuits were robustly reproducible. I made many of those by starting
with a lower value and grinding into the carbon to raise the resistance.

The story I heard was older than that.

I have always thought that composition resistors were built, and them
measured for value, instead of being built for a certain value, though
I don't know that I really understand the process.

-- glen

 

[Mark Fergerson]

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

... and I thought it because I was getting to be an old fart. ;-)

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

Mark L. Fergerson

 

[John Woodgate]

I read in sci.electronics.design that Mark Fergerson <[email protected]>

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

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.

 

[Jim Thompson]

I read in sci.electronics.design that Mark Fergerson <[email protected]>


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

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

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).

...Jim Thompson

 

[John Woodgate]

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

God used part of it to encode the rainbow.

But who wants a 234567800 Mohm resistor?