| Author |
Message |
Peter K.
Guest
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 Posted:
Sat Dec 17, 2005 1:16 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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Al Clark <dsp@danvillesignal.com> writes:
| Quote: | I still call powering up a circuit the first time, the smoke test.
Its been a long time since one actually smoked (they don't always work,
but they tend to be a lot more benign).
|
When I was tutoring 1st year engineering labs, by far the biggest
mistake students had made when they said "it doesn't work" was to
leave the power supply off.
I _know_ it's bad, but I used to shout <BANG> when they turned the
power supply on. :-)
And nine times out of ten, everything worked. There were just two
times I remember anything "letting the smoke out". Once it was an
electrolytic capacitor that went <BANG> and the other time the
students got some diodes to glow faintly red... and they we'ren't
SUPPOSED to be LEDs.
Ciao,
Peter K. |
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Vladimir Vassilevsky
Guest
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| Posted:
Sat Dec 17, 2005 1:16 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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Peter K. wrote:
| Quote: | When I was tutoring 1st year engineering labs, by far the biggest
mistake students had made when they said "it doesn't work" was to
leave the power supply off.
I _know_ it's bad, but I used to shout <BANG> when they turned the
power supply on. :-)
|
The engineers who work on the power electronics are usually very good
engineers. Many of them are stutterers also. Perhaps the folks who were
not that good just didn't survive.
VLV |
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Richard Owlett
Guest
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| Posted:
Sat Dec 17, 2005 1:16 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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Al Clark wrote:
[*SNIP*]
| Quote: | Engineering is the art of making what you want from things you can
get.
That's why engineering was more fun in the old days. It was tougher.
Its wasn't tougher, just different.
One of the changes that I think will affect our profession is that it is
very difficult for a kid to get started if he wants to build hardware.
You probably need several thousand dollars of used equipment to start
(microscope, good soldering iron, etc.) This is a lot of money for a 16
year old kid.
Of course, we didn't have personal computers.....
|
*WHAT* ?
just how do you justify that monetary outlay?
I'll use myself as an example ;}
I am routinely giving grief to regulars on
comp.dsp
comp.speech.research
comp.speech.users
comp.lang.forth
sci.geo.satellite-nav
alt.satellite.gps
comp.arch.embedded
I have not expended dollars, but I've made some *THINK* ;)
| Quote: |
There was no Digikey and you had to make do with whatever the radio or
TV industry used.
I used to go to the local shop for parts, then Radio Shack....
I remember concocting state registers and ring
counters with Ge transistor because they wanted over $5 for one RTL
chip which exceeded my allowance. And even at that price they probably
were from a 're-labeler'. Bulk waste days were field days because one
could harvest tons of tubes for free and create cool stuff with them.
Regards, Joerg
http://www.analogconsultants.com
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Joerg
Guest
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| Posted:
Sat Dec 17, 2005 1:16 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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Hello Jerry,
| Quote: | Hands-on matters. Today we have college students and beyond who glibly
compute complex baseband signals on a single twisted pair, and wonder
how to proceed with their simulations. It's east to forget that no
matter how small things become, they're still made up of parts that
interact.
|
I had several cases where they could not understand my module specs. And
my prose is quite ok since even (older) mechanical engineers never have
problems with that. Some of the new grads can't even solder. It's pathetic.
| Quote: | Acquaintances and neighbors were aghast that I let my kids use tools
like saws and chisels before first grade. I explained that I was careful
to teach them how to use such tools -- in general and specifically --
without hurting themselves. I too drew a line. I allowed them to use
tools that could cut a finger, but not one that could cut a finger off.
|
Probably because you were good parents and your kids paid attention to
what you taught them. I remember a trip in the mid west when a big truck
pulled up next to us at the market. A little boy hopped out, maybe 14 or
15. "Are you allowed to drive that thing?" "Ahm, well, ahem, pa kinda
ruined his back and we really need some stuff for the farm". He had been
in front of us for 10 miles or so and all I could say is he drove like a
pro, very safely.
Regards, Joerg
http://www.analogconsultants.com |
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Joerg
Guest
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| Posted:
Sat Dec 17, 2005 1:16 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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Hello Al,
| Quote: | Its wasn't tougher, just different.
|
Maybe not tougher but more expensive. Even in 2005 Dollars our
allowances were much smaller than today's.
| Quote: | One of the changes that I think will affect our profession is that it is
very difficult for a kid to get started if he wants to build hardware.
|
Nah. Recently I needed some CD4000 chips right away so I drove into town
and picked them up at an electronics store. All between 30 and 50 cents
a piece. When I grew up you couldn't touch any of these for under $4.
Just imagine what that would be in 2005 Dollars.
Now you can buy a uC for a couple Dollars and program it for free by
just making a serial cable and hooking up a little level translation.
Back then any kind of processor cost more than a decent bicycle and
wouldn't work without external RAM. I paid more than $25 for one lone
memory chip which offered a whopping 1k (kilobits, not kilobytes). I'd
really needed 2k but that was way out of reach. Oh, and I had to punch
in the data with buttons until blisters showed up. The only computer was
at my fathers work, a huge IBM mainframe.
When I built a small frequency counter I had to wait a few weeks before
its sensitivity could become better than 1Vpp. That's because an AF126
was almost $10 at the local radio repair store. Too much. So when the
snow and ice became manageable I did a (rather scary) bicycle tour of
about 20 miles because the store in town had it for under $5. That AF126
had to be treated like a princess on the pea so as not to fry it, ever.
I mounted it in a socket so it could be used in another circuit while I
didn't need to run the counter.
Nowadays you can get a whole bag of similar speed BJTs for a Dollar or two.
Regards, Joerg
http://www.analogconsultants.com |
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Al Clark
Guest
|
| Posted:
Sat Dec 17, 2005 1:16 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
|
|
Richard Owlett <rowlett@atlascomm.net> wrote in
news:11q665ofjhmcfb4@corp.supernews.com:
| Quote: | Al Clark wrote:
[*SNIP*]
Engineering is the art of making what you want from things you can
get.
That's why engineering was more fun in the old days. It was tougher.
Its wasn't tougher, just different.
One of the changes that I think will affect our profession is that it
is very difficult for a kid to get started if he wants to build
hardware.
You probably need several thousand dollars of used equipment to start
(microscope, good soldering iron, etc.) This is a lot of money for a
16 year old kid.
Of course, we didn't have personal computers.....
*WHAT* ?
just how do you justify that monetary outlay?
|
Microscope with Boom & Light: $500-$1000
Soldering Station $150
Oscilloscope $250-$750
Handtools $50-$250
Signal Generator, Multimeter, etc.
Solder, Flux, Antistat Mat, etc...
This is before buying parts.
Sure, you can still buy thru hole parts for many things, but I think
you will find that you cannot avoid SMT parts for very long.
--
Al Clark
Danville Signal Processing, Inc.
--------------------------------------------------------------------
Purveyors of Fine DSP Hardware and other Cool Stuff
Available at http://www.danvillesignal.com |
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Jerry Avins
Guest
|
| Posted:
Sat Dec 17, 2005 7:53 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
|
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Peter K. wrote:
| Quote: | Al Clark <dsp@danvillesignal.com> writes:
I still call powering up a circuit the first time, the smoke test.
Its been a long time since one actually smoked (they don't always work,
but they tend to be a lot more benign).
When I was tutoring 1st year engineering labs, by far the biggest
mistake students had made when they said "it doesn't work" was to
leave the power supply off.
|
When I was doing audio service, a fellow brought me a newly wired
Heathkit power amplifier to fix. When I asked him what the problem was,
he said, "I don't know. I didn't have the guts to turn it on."
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ |
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Ron N.
Guest
|
| Posted:
Sat Dec 17, 2005 9:15 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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Steve Underwood wrote:
| Quote: | When I was 12, my father let me build valve/tube equipment running on
400V to 500V. He was an electro-mechanical engineer, so he fully
understood what he was letting me do. There is *absolutely* *no* *way*
my two kids are going to do that when they are 12 :-)
|
I attended a talk given my Gorden Moore recently. When asked how
he got interested in chemistry, he talked about using the stuff in
his chemistry set to blow things up. When asked later about
the declining interest in science education in the US, he lamented
that maybe it's because you can't get the fun chemistry sets any
longer.
IMHO. YMMV.
--
rhn A.T nicholson d.O.t C-o-M |
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Joerg
Guest
|
| Posted:
Sun Dec 18, 2005 1:15 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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|
Hello Tim,
| Quote: | I had a coworker for a while who could make a perfect 120-cycle buzz,
loudly, just like a piece of power electronics about to go up in smoke.
I think if we hadn't been doing stuff that was all DC we would have
dragged him out and shot him...
|
This was from the days when smoking was still allowed in labs: Engineer
drinks coffee. Nature calls. While engineer is at the ceramics
department someone shoves a screw cap with a not-quite-extinguished butt
under the prototype. Engineer comes back. Smoke billowing out of
prototype. Engineer panics and rips all supplies off.
Regards, Joerg
http://www.analogconsultants.com |
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Joerg
Guest
|
| Posted:
Sun Dec 18, 2005 1:15 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
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|
Hello Peter,
| Quote: | I _know_ it's bad, but I used to shout <BANG> when they turned the
power supply on. :-)
|
My first boss used to walk around, look over your shoulder, reach onto
the board, touch a chip or an electrolytic, quickly retract his hand and
say "ouch, why does this get hot?"
(None of this ever got hot, usually...)
Regards, Joerg
http://www.analogconsultants.com |
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Joerg
Guest
|
| Posted:
Sun Dec 18, 2005 1:15 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
|
|
Hello Al,
| Quote: | Microscope with Boom & Light: $500-$1000
|
How 'bout #3 magnifier glasses (a buck at the Dollar Store) and a loupe
on the swivel arm of a discarded drafting table lamp (pretty much free)?
Regards, Joerg
http://www.analogconsultants.com |
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Tim Wescott
Guest
|
| Posted:
Sun Dec 18, 2005 1:15 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
|
|
Vladimir Vassilevsky wrote:
| Quote: |
Peter K. wrote:
When I was tutoring 1st year engineering labs, by far the biggest
mistake students had made when they said "it doesn't work" was to
leave the power supply off.
I _know_ it's bad, but I used to shout <BANG> when they turned the
power supply on. :-)
The engineers who work on the power electronics are usually very good
engineers. Many of them are stutterers also. Perhaps the folks who were
not that good just didn't survive.
VLV
-- and the folks who aren't that nervous? |
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com |
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Tim Wescott
Guest
|
| Posted:
Sun Dec 18, 2005 1:15 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
|
|
Peter K. wrote:
| Quote: | Al Clark <dsp@danvillesignal.com> writes:
I still call powering up a circuit the first time, the smoke test.
Its been a long time since one actually smoked (they don't always work,
but they tend to be a lot more benign).
When I was tutoring 1st year engineering labs, by far the biggest
mistake students had made when they said "it doesn't work" was to
leave the power supply off.
I _know_ it's bad, but I used to shout <BANG> when they turned the
power supply on. :-)
And nine times out of ten, everything worked. There were just two
times I remember anything "letting the smoke out". Once it was an
electrolytic capacitor that went <BANG> and the other time the
students got some diodes to glow faintly red... and they we'ren't
SUPPOSED to be LEDs.
Ciao,
Peter K.
|
I had a coworker for a while who could make a perfect 120-cycle buzz,
loudly, just like a piece of power electronics about to go up in smoke.
I think if we hadn't been doing stuff that was all DC we would have
dragged him out and shot him...
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com |
|
| Back to top |
|
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Jerry Avins
Guest
|
| Posted:
Sun Dec 18, 2005 7:29 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
|
|
Joerg wrote:
| Quote: | Hello Tim,
I had a coworker for a while who could make a perfect 120-cycle buzz,
loudly, just like a piece of power electronics about to go up in smoke.
I think if we hadn't been doing stuff that was all DC we would have
dragged him out and shot him...
This was from the days when smoking was still allowed in labs: Engineer
drinks coffee. Nature calls. While engineer is at the ceramics
department someone shoves a screw cap with a not-quite-extinguished butt
under the prototype. Engineer comes back. Smoke billowing out of
prototype. Engineer panics and rips all supplies off.
|
A long piece of spaghetti stock artfully arranged with one end under the
chassis and the other where it can be blown into allows for more precise
timing.
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ |
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Peter K.
Guest
|
| Posted:
Sun Dec 18, 2005 7:36 am Post subject:
Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF |
|
|
Joerg <notthisjoergsch@removethispacbell.net> writes:
| Quote: | This was from the days when smoking was still allowed in labs:
Engineer drinks coffee. Nature calls. While engineer is at the
ceramics department someone shoves a screw cap with a
not-quite-extinguished butt under the prototype. Engineer comes
back. Smoke billowing out of prototype. Engineer panics and rips all
supplies off.
|
Yes, I heard a similar story... but it involved someone putting one
end of a vaccuum cleaner hose under a piece of equipment, standing
behind a partition and blowing smoke from their cigarette into the
other end of the hose (so that it looked like smoke was coming from
the piece of equipment).
:-)
Ciao,
Peter K. |
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