Old-fart electronics quiz

[Jerry Avins]

Roger Johansson wrote:

...

The only problem we have here is too much influence from american culture.
The tv channels seem to be full of violence in american-made movies and
tv-series. The children in the schoolyards wear baseball caps and train
karate kicks on the shorter kids.

If Swedish television managers are like ours, they are in the business
of giving Swedes what Swedes want. The Swedish kids practicing Oriental
chops on their fellows are under the supervision of Swedish teachers,
who apparently permit, or at least tolerate, the practice. Why do you
suppose that Americans bear responsibility for this?

Jerry

 

[James Meyer]

Is that the device where the three leads exit the base in a straight
line with the centre one slightly off-set towards one of the outer
leads and a paint-spot on the edge near the bottom of the
encapsulation for assisting in pin identification? Mullard, wasn't it?

Mullard sounds right. Most of the packages of the time were like you
described.

Jim

 

[Ben Bradley]

Crudity, political correctness, etc aside: You probably won't need to
teach the color code to budding techs and engineers very much longer
since thru hole parts are rapidly disappearing and resistors are marked
with numbers. The colors of modern thru hole resistors are harder to
distinguish than the old carbon comps as well and very few capacitors use
color coding at all.

You can get colored ribbon cable that has the wires colored
consecutively in the resistor color code (first wire is black, next is
brown, next is red,... and repeats with black again every 10 wires)
for easily locating the Nth wire in the cable, and many audio "snakes"
(cable bundling many audio signal cables) have cables colored in order
(channel 1 black, 2 brown, 3 red, etc) so if you know the color code
you can plug the cables into the mixer in the correct order easily and
quickly.
Does anyone have any other non-component-value examples of the
color code being used?

And I never even met a girl named Violet......

The way Violet is used in the mnemonic must have really put that
name out of favor. <I'm half joking - surely most parents naming girls
have never heard of the resistor color code or this mnemonic>

 

[Precious Pup]

2. What is a reflex amplifier?

A stupid dual frequency (RF-IF & BB) receiver design that died 60 years ago?


See ch28 of Radiotron Designer's Handbook, (c) 1953 4th ed.

 

[Jon Harris]

Thanks to all who answered. I thought it was a mnemonic from the
context in Randy's post, but I neglected to make the connection to
the English color names because English is not my mother tongue.
Since I'm minoring in EE, I'll probably be related a native relative
of that -disgusting- sentence sooner or later


Jim Weir gave another version which I find indeed harder to remember.
If anyone knows yet another one, I'd like to hear it!

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!

 

[Allan Herriman]

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.

 

[Active8]

On 18 Jan 2004 14:16:22 -0800, [email protected] said...

Do tell us more...


Regards, NT

I'll do better. Google on Harold Black also on Feedback Systems
EE214 Fall 2002

That ought to get you there. He did develop the feedforward amp,
too. The problem at the time was closely matching two tubes. US
Pat. #1,686,792

 

[Roger Johansson]

If Swedish television managers are like ours, they are in the business
of giving Swedes what Swedes want. The Swedish kids practicing Oriental
chops on their fellows are under the supervision of Swedish teachers,
who apparently permit, or at least tolerate, the practice. Why do you
suppose that Americans bear responsibility for this?

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.

 

[JeffM]

Can't you make an LC Pierce?

John Larkin

I can't remember seeing one that didn't use a crystal.
I always associated them together.
Maybe we need Win to call this one.

 

[John Woodgate]

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:

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 Woodgate]

I read in sci.electronics.design that Precious Pup

A stupid dual frequency (RF-IF & BB) receiver design that died 60 years ago?


See ch28 of Radiotron Designer's Handbook, (c) 1953 4th ed.

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

 

[I. R. Khan]

If Swedish television managers are like ours, they are in the business
of giving Swedes what Swedes want. >

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.

 

[glen herrmannsfeldt]

John Woodgate wrote:

(snip)

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.

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

 

[Allan Herriman]

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.

I think that stopped with the introduction of laser trimmed film
resistors. I've been using surface mount versions of the same since
the late '80s, and I probably haven't read a resistor colour code more
than a few times in the last decade.

Regards,
Allan.

 

[Active8]

A system for remembering the color code for resistors. Look at the first
letter of each word, Black, Brown, Red, Orange etc..

A typical example of american culture, a combination of bad taste, violence
and foul language.

Well, the way *this* American learned it *first* was

Big boys race our young girls but violet generally wins

 

[Active8]

Ahh- well you have not been told the rest of the rhyme which is : Get
Some Now for the tolerance band- Gold Silver No Color...

ok, big boys race our young girls but violet generally wins... go
shower now.

 

[Rick Lyons]

We talk about sex of course but the favorite topic of discourse seems
to be politics and weather.

Sounds reasonable. I've always held the
belief that there are only three
really meaningful topics of conversation:

sex
politics
religion

[-Rick-]

 

[Rick Lyons]

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]

Add some misdirected patriotism, megalomania and paranoia and you have the
typical american participator in usenet newsgroups.

I suppose the only patriotism that is *not* misdirected is yours?

I didn't know that Euro-weenieism had spread to Sweden, but it looks
like it has.

I missed your post initially because I see that I had kill-filed you
many months ago.

GFY!

...Jim Thompson

 

[Rick Lyons]

We have such a small and insignificant country so we have no use for
patriotism, it wouldn't be worth the effort.

We have also been neutral for so long that we have not been taught to
always agree with either the west or the east.

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.

I agree with you regarding American television.

[-Rick-]

 

[John Woodgate]

I read in sci.electronics.design that glen herrmannsfeldt

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.

Indeed; where different tolerances are available, it depends on demand
whether you get on-target or off-target product. But if you wanted 1000
240 kohm, they just put 1000 220 kohm and 1000 270 kohm through a test
set for 240 kohm +/-10% and either coded or re-coded the output. You
would be *likely* to get a somewhat bimodal distribution of values.