What's on your test bench?
Phil O. Sopher
test equipment, AF Genny, RF Genny, Freq Counter, High
Impedance Voltmeter, Wheatstone Bridge, Oscilloscope.
None of these is particularly small and all are at least a 6" cube.
It seems to me that the same functionality could be achieved
these days with perhaps just a few inches of bench space, but,
would it be of any use?
The eqpt I gathered together dates very much from the days of
designing circuitry with individual componenents (R, L, C, BJT)
and offers test and validation at that level, but nowadays we don't
work at that level (even op amps have been around for that 40 year
period).
So, what do you have on your test bench these days, how big is it,
did you design it yourself, and what would you recommend to the
budding circuit designer of today who isn't in the industry and therefore
does not have access to Spice or Matlab to validate their designs?
a7yvm1...@netzero.com
> Over a 40 year period of interest, I've gathered some
> test equipment, AF Genny, RF Genny, Freq Counter, High
> Impedance Voltmeter, Wheatstone Bridge, Oscilloscope.
>
> None of these is particularly small and all are at least a 6" cube.
>
> It seems to me that the same functionality could be achieved
> these days with perhaps just a few inches of bench space, but,
> would it be of any use?
>
> The eqpt I gathered together dates very much from the days of
> designing circuitry with individual componenents (R, L, C, BJT)
> and offers test and validation at that level, but nowadays we don't
> work at that level (even op amps have been around for that 40 year
> period).
True, I design at the "specify a function, go to Digikey" level.
> So, what do you have on your test bench these days, how big is it,
Tektronix 547 with 15 plugins: Dual and quad input amps, differential
amp, spectrum analyzers from audio to 10GHz. (Huge)
HP5316 counters (medium)
GPS disciplined 10MHz OCXO. (medium, needs antenna)
USB logic analyzer, Rigol 100MHz scope (small)
> did you design it yourself, and what would you recommend to the
> budding circuit designer of today who isn't in the industry and therefore
> does not have access to Spice or Matlab to validate their designs?
What?
http://www.linear.com/designtools/software/ltspice.jsp
http://www.gnu.org/software/octave/
OK, so that's not really Matlab, but it's all I could think of in my
present "booting consciousness" state.
Phil Hobbs
LTSpice is free, and so is Gnu Octave. Why doesn't the budding designer
download a copy of each?
I have one 19-inch rack nearly full of aged-to-perfection high end HP
and Tek gear. Not counting the Tek 11802 sampling scope (which is a
special case) I paid about 2.5 cents on the dollar for it. (See the
list I posted here on October 1st.)
If the budding designer can lay off beer for a month, he can have a good
quality analog scope, +- variable power supply, pulse generator, DMM,
and temperature-controlled soldering iron, courtesy of eBay. I'd sure
have learned faster if I'd had all that stuff as a kid.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net
JW
<inv...@invalid.invalid> wrote in Message id:
<hde9q4$t98$1...@news.eternal-september.org>:
>So, what do you have on your test bench these days, how big is it,
>did you design it yourself, and what would you recommend to the
>budding circuit designer of today who isn't in the industry and therefore
>does not have access to Spice or Matlab to validate their designs?
At home:
Lecroy 9374M scope
Keithley 2000 DMM
HP 5385A opt 004 counter
Agilent 6643 power supply
HP 8656B
General Radio resistor decade box
Other than the decade box, all bought defective on Ebay and repaired by
myself.
At Job #1
Agilent 54810A scope
Valhalla 2701B DC calibrator
HP 745C AC calibrator
Fluke 45 DMM
Philips PM 2534 DMM
Some crappy old B&K power supply
Fluke 9100 and various pods
At job #2
Lecroy 9354L scope
Keithley 2010 DMM
Kiksui 300W electronic load
HP 437 Power meter
HP 8350A generator with various plug-ins
EIP 545 counter
EDC MV106 voltage standard.
Amrel +-30V 3A power supply (forget model #)
HP 5005 signature analyzer
Bob Parker's blue ESR meter
Don't really design anything, I'm a test equipment repair technician.
MooseFET
Do we also count the floor near the test bench?
On the bench I have:
A Tek digital phosphor scope and an old-old Philips scope that is only
good for 25 MHz. Both are connected to the system being developed. I
need to watch signals in two unrelated time domains.
There is a Fluke 45(IIRC) DVM with RS-232 output that I can record on
the PC. I need to monitor a DC voltage over the time frame of hours
and I don't want to do all that writing.
The PC has 4 RS-232 ports. Two of them run to the system. (Not
counting the Fluke)
Beside the PC is a laptop that is currently not in use but its serial
port is the reason it is sitting there.
The power supply is a B&K.
On the floor is a shield can the size of a modest water heater.
Filed away in a cabinet is a bunch of stuff but one that comes to mind
is a calibrated hair drier. The temperature of the air it puts out is
just about exactly 60C.
MooseFET
<pcdhSpamMeSensel...@electrooptical.net> wrote:
[....]
> LTSpice is free, and so is Gnu Octave. Why doesn't the budding designer
> download a copy of each?
Yes to both of those.
Octave is a great language for quickly coding up the math of
something.
Also learn a little about gnuplot. It is great for making graphs of
things you can't do with a spread sheet.
Also you want to have a copy of the latest OpenOffice spreadsheet. It
can do really big ones and will import ASCII.
Fred Bartoli
What? It's not calibrated in Fahrenheits?
--
Thanks,
Fred.
George Herold
Cool, I never heard of Octave. Steep learning curve? I've never used
Matlab or similar software. When I need math functions more
complicated than my calculator I fire up an old version of QuickBasic
(4.5?) under DOS. I did a little bit of C coding back in the 80's,
but never needed the speed, (or the slows.. I found it easier to debug
the basic code.)
George H.
Phil Hobbs
Octave is an open-source Matlab clone, originally developed as
courseware. It has a pretty good user base and reasonable developer
support. It can run most Matlab M-files unaltered. Earlier versions
had trouble with plotting, but the latest ones are quite good, though
not as good as Matlab. (On the other hand, they don't cost $2k.)
Octave/Matlab are matrix-oriented, so they work more efficiently with
vector and matrix operations (not necessarily linear ones). They do
have loops and so on, but they run at QuickBasic type speeds instead of
Matlab type speeds. Octave/Matlab are nearly as fast as compiled code
for vectorish stuff.
Matlab is great if you need the more advanced extensions, but paying $2k
for the basic program is completely unnecessary otherwise.
Joel Koltner
news:4mglf5losmns7t1s7...@4ax.com...
> Other than the decade box, all bought defective on Ebay and repaired by
> myself.
I'd be interesting in hearing what sorts of problems they had, if you still
recall... mainly as an indication of, "when it's sold as busted on eBay, just
*how* busted does it tend to be?"
---Joel
Spehro Pefhany
D from BC
If I tell should I install extra locks on the door afterward? :P
D from BC
Amateur smps designer
British Columbia, Canada
Posted to sci.electronics.design
a7yvm1...@netzero.com
> can do really big ones and will import ASCII.
While OO is great, it also has bloat and annoyances (UI gets confused
with multiple monitors).
You can get Gnumeric as a great stand alone spreadsheet.
MooseFET
> On Nov 11, 10:19 am, MooseFET <kensm...@rahul.net> wrote:
>
>
>
> > On Nov 11, 5:40 am, Phil Hobbs<pcdhSpamMeSensel...@electrooptical.net> wrote:
>
> > [....]
>
> > > LTSpice is free, and so is Gnu Octave. Why doesn't the budding designer
> > > download a copy of each?
>
> > Yes to both of those.
>
> > Octave is a great language for quickly coding up the math of
> > something.
>
> > Also learn a little about gnuplot. It is great for making graphs of
> > things you can't do with a spread sheet.
>
> > Also you want to have a copy of the latest OpenOffice spreadsheet. It
> > can do really big ones and will import ASCII.
>
> "> Octave is a great language for quickly coding up the math of
>
> > something."
>
> Cool, I never heard of Octave. Steep learning curve?
The learning curve isn't too bad. If you can do basic, you should
be able to learn to use Octave.
Octave defaults to printing the results unless you put a semicolon on
the end.
Here's a plot of sin()
octave:1> X=1:0.1:6 # Make an array of 1 to 6 in 0.1 size steps
octave:2> Y=sin(X) # Find the sin() of each value
octave:3> plot(X,Y) # Make a pretty plot
Functions are made like this:
octave:7> function Z=DoThing(A,B)
> Z=A+B
> endfunction
A B and Z are all matrix values so DoThing would add two matrixes.
MooseFET
> MooseFET a écrit :
No strangely enough the 45C and 60C temperatures needed to be reported
in C degrees.
We do have some tape measures in decimal feet just in case you need to
measure off 63.5 feet of #40 copper wire.
John Larkin
<inv...@invalid.invalid> wrote:
ftp://jjlarkin.lmi.net/DSC01371.JPG
Parts cabinet to the left, whiteboard to the right. Out of sight is a
bunch of cables and adapters and other small test gear, DVMs and RLC
meters and such. Big stuff can be wheeled up on a cart as necessary.
This is an Ikea "computer workstation" and parts cabinet.
I do a lot of live-bug breadboarding on hacked copperclad FR4 and use
the Bellin SMT adapters for wiring up small stuff.
ftp://jjlarkin.lmi.net/BB_fast.JPG
John
D from BC
White board?
This is the era of BIG LCD displays and schematic software. :P
Which brings me to..
No computer monitor on the bench???
I suppose it'll get accidently poked with the soldering pen.
krw
<inv...@invalid.invalid> wrote:
At home? Nothing, if you don't count a couple of Fluke-77s and a
couple of HF DVMs (left visible, used as bait). I don't do
electronics at home. I get enough in the 55 hours/week or so at work.
JW
<zapwireD...@yahoo.com> wrote in Message id:
<fSCKm.166325$Gs.2...@en-nntp-01.dc1.easynews.com>:
>"JW" <no...@dev.null> wrote in message
>news:4mglf5losmns7t1s7...@4ax.com...
>> Other than the decade box, all bought defective on Ebay and repaired by
>> myself.
>
>I'd be interesting in hearing what sorts of problems they had, if you still
>recall...
The Lecroy 9374M scope had a problem with the battery back up circuit on
the CPU board. Lecroy 93XX (and possibly other Lecroy) scopes are weird in
that if the rechargeable battery falls below or above a certain voltage it
locks up the CPU. In fact, if you disconnect the battery when it's up and
running, the scope will freeze up. (Agilent 545XX scopes also lock up when
the battery dies) This particular one's voltage would surge up to almost
5V on a power-up and stay there, possibly back-feeding or latch-up from
the real time clock - I found that putting a 33uF tantalum on the Vbat
voltage would prevent that momentary surge. The floppy drive was also bad,
I figured out how to adapt a standard slim floppy drive used in laptops to
replace the oddball Epson drive.
The Keithley 2000 would fail random self tests - a power supply re-cap
fixed it. I just fixed a Keithley 2001 MEM2 with the exact same issue, but
that one's for sale now. I don't need that kind of accuracy, and it's
missing some functions that the 2000 has.
The HP 5385A counter had a shorted over-voltage protection zener in the 5V
digital supply.
The Agilent 6643 power supply had a busted LCD display. Rather than spend
$85 for a new one from Agilent, I found that their 3488A switch unit
shares the same display - they can be had for peanuts; nobody wants 'em it
seems. After replacing the display the supply would error out in
overvoltage mode when programmed to output a voltage greater than 2VDC, a
bad op-amp in the sense inputs.
The HP 8656B, can't recall that one...
>mainly as an indication of, "when it's sold as busted on eBay, just
>*how* busted does it tend to be?"
More often than not, much of the stuff is quite repairable as long as
someone hasn't already made a mess of it in a botched repair attempt. The
only piece I bought and was never able to repair is a Tek 2430A which had
bad CCDs - the chips are pretty much unobtanium these days. I'd say the
most likely failures are:
1. Battery failures
2. Electrolytic cap failures
3. Shorted or open semiconductors in power supply circuits.
4. Oxidation of contacts.
5. Mechanical failures
Working part time for one of the used test equipment companies has allowed
be to gain quite a bit of experience and knowledge in certain "magic
bullet" fixes. Those are fixes where a particular piece is notorious for
certain failures and cures. I'm always on the lookout on Ebay for those.
John Larkin
I scribble the schematic of a breadboard and correct it as I go, and
list measurements or notes on the whiteboard, then photograph
everything... the breadboard, scope waveforms, the whiteboard. If any
of it is interesting enough, we release it to an engineering notes
folder on a server, or dump relevant bits into our parts database.
Some of the whiteboard pics and scope shots go directly into customer
proposals. They seem to enjoy it, a break from PowerPoint.
>Which brings me to..
>No computer monitor on the bench???
I'll add a laptop if I'm talking to a serial box or background
debugging firmware or things like that.
>I suppose it'll get accidently poked with the soldering pen.
I don't have a lot of room - this is in the corner of my office - so I
bring in equipment as needed. The big sampling scope weighs about 80
pounds, and the Mantis is bolted down, so they're permanent.
John
John Larkin
Agreed. I have an Extech DVM with thermocouple probe, handy for
household work and cooking, and a bench power supply, for testing
light bulbs and charging batteries. But no electronics!
John
George Herold
>
> - Show quoted text -
The only times I do electronics at home is when I 'mistakenly' power
up a new PCB on Friday afternoon. Of course something doesn’t work,
and I know I’ll obsess about over the weekend. The easy solution is
to pack up pcb, scope and what ever else I’ll need and schlep it
home.
George H.
krw
Funny. I expected flak from you. ;-)
krw
If necessary I just go into work over the weekend. If there is
something that really needs to be done it's no big deal.
John Larkin
There's always LT Spice if I need an electronics fix on weekends. And
I'm only about 12 minutes from work.
I plan to build a barn behind the cabin in Truckee, and I'll probably
have a lab there, so I can play with circuits on days when skiing
conditions aren't good.
John
Jamie
krw
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
I have the FPGA tools from the various manufacturers[*] loaded on my
laptop but I've never used them in anger. I'm 13 miles, half
interstate.
>I plan to build a barn behind the cabin in Truckee, and I'll probably
>have a lab there, so I can play with circuits on days when skiing
>conditions aren't good.
Isn't that the time to read a book by the fire?
[*] Yikes, are the FPGA sales types hungry! I'm getting calls every
day from the four vendors.
Pieyed Piper
http://www.home.agilent.com/upload/cmc_upload/E4440A_800x583.jpg
About once a week. 26GHz
George Herold
>
> - Show quoted text -
I live out in the sticks. Once I get home for the weekend I really
don't like going back in... of course if it's important.
George H.
George Herold
>
> - Show quoted text -
Hmm, 45 minute's away. Of course there's 30 acres of land, half woods
and a beautiful stream and gorge behind the house. I think my
favorite thing is to take a notebook down to the stream and scribble
thoughts of the day.
George H.
Tom Gootee
These are extremely handy:
http://www.aeroflex.com/ats/products/product/Broadband_Test/Broadband_Signal_Analyzers~540.html#
with 600 MHz recording/playback/analysis bandwidth, anywhere up to 18
GHz. But they are a bit expensive.
We have some E4440 spec ans, but mostly use the E4407B models, since
we have tons of those.
Jamie
Are you trying to say I can't use my Grid Dip meter to perform that job? :)
John Larkin
How is support on that thing? We bought an Aeroflex spectrum analyzer
and it's buggy and has some problems. They can't support it because
it's made by somebody else in Korea who they seem to have little
influence over.
John
Pieyed Piper
wrote:
>On Nov 12, 9:36�pm, Pieyed Piper
Our lab has like 40 or so similar such Items and we also use many of
their components as well.
Pieyed Piper
Only if your name is Dippity Doo Dah.
Tom Gootee
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Sun, 15 Nov 2009 09:43:51 -0800 (PST), Tom Gootee
>
>
>
>
>
> <t...@fullnet.com> wrote:
> >On Nov 12, 9:36 pm, Pieyed Piper
> ><pieyedPi...@thebongshopattheendoftheuniverse.org> wrote:
> >> I put one of these in about every other rack.
>
> >>http://www.home.agilent.com/upload/cmc_upload/E4440A_800x583.jpg
>
> >> About once a week. 26GHz
>
> >These are extremely handy:
>
>
> >with 600 MHz recording/playback/analysis bandwidth, anywhere up to 18
> >GHz. But they are a bit expensive.
>
> >We have some E4440 spec ans, but mostly use the E4407B models, since
> >we have tons of those.
>
> How is support on that thing? We bought an Aeroflex spectrum analyzer
> and it's buggy and has some problems. They can't support it because
> it's made by somebody else in Korea who they seem to have little
> influence over.
>
>
> - Show quoted text -
Well, the support we get is really excellent. But we are a Very Large
customer of theirs. Those digital sampling/analysis/playback units
are made by Aeroflex themselves, right here in the USA (CA). They
bought out the original company ("Celerity", maybe?), which was
founded by the architect/designer of those systems, Jack Anderson. He
used to come visit us regularly, before he unexpectedly and tragically
died, just last year, way too young. He was a truly-great person; a
remarkable, wonderful, unassuming, modest, dedicated, and super-
intelligent man.
We don't buy many of their other products, except for programmable
switched attenuators, which I believe are really a Weinschel product.
We also use some of their fixed high-power attenuators.