Date   

Definition of a capacitor (was: Re: Re: 2465B power supply)

Brad Thompson <brad.thompson@...>
 

Hello--

The current discussion prompted me to rework an old component-engineering definition
that originally refers to connectors...

Capacitor (n): a source of trouble that accumulates and releases electrical charge produced by,
or used by, other sources of trouble....

73--

Brad AA1IP


Re: New to the group with a few questions

J Mcvein
 

The part is 0.095 long. The standard wrench sizesbelow 0.050 are 0.035, and 0.028 across the flats.The 0.028 fits a 0-80 screw, for reference, so a0.035 would be a good try.
JimMc


From: "Tom Jobe tomjobe@gmail.com [TekScopes]" <TekScopes@yahoogroups.com>
To: TekScopes@yahoogroups.com
Sent: Wednesday, October 21, 2015 7:10 PM
Subject: Re: [TekScopes] Re: New to the group with a few questions

Hello Leetmaster,
If you were able to remove the 3-48 set screw somehow, a 3/32 (.0935"
across the flats nominally) Allen wrench would not even fit into the
empty threaded hole, so something must be wrong with the details of what
you think you have.
In my very limited experience, Tektronix only used two small set screw
sizes on the control knobs and they use either a .050" or a 1/16"
(.0635" nominal size) Allen wrench.
The only small Allen wrenches i have seen that really work well are the
ones ground from solid tool steel that the radio control modelers use.
You can buy them at your local RC model shop, or online... I have done both.
The lesser Allen wrenches up through even the Whia and equivalent
premium brands are just not up to the job on the smaller size hex
wrenches in my experience.
tom jobe...




On 10/21/2015 1:08 PM, leetmaster4004@yahoo.com [TekScopes] wrote:

I did know that it can only go in the vertical slot. It looks like
they just re-purposed that button to turn off the output from the
module. That seems to be the sole functional difference between the
5CT1N and the 7.

An additional problem I forgot to bring up in my first post.


I picked up a 7D01 recently and am stripping it down to make some
repairs. I have two set screws that I can't find the correct size hex
wrench to remove. The manual states they are "SETSCREW :3-48 X 0 .095
INCH,HEX SOC STL"

3-48 is the set-screw size and thread spacing but I haven't been able
to find a hex wrench of size .095 inch. Has anyone come across the
right tool for these and if so where do I get one?









------------------------------------

------------------------------------


------------------------------------

Yahoo Groups Links








[Non-text portions of this message have been removed]


Re: 067-0513-00 Pulse Generator

Roger Evans
 

I actually have one of the ADCMP572 devices mentioned earlier. They may only be $16 for the bare IC but they are VERY small and need careful PCB layout to get 50 ohm traces from the pins to the SMA sockets.

What I have is an evaluation board costing somewhere around $250 which is on loan from work, I imagine the board is built to a very good spec if the aim is to encourage its use in high speed designs. It is about 12cm square with six SMA sockets each about 4cm from the central IC and each with curving rather than straight segment tracks. Driven from a standard 5V CMOS input I see about 75ps rise and fall times (10-90%) with both an S4 and an S6 sampling head. If you believe you can subtract the nominal rise times for the sampling heads (and I have never been able to test them) then this is about 70psec for the ADCMP572 transition time. At this speed I don't see any difference between a 15cm semi-rigid cable and 30cm flexible between the evaluation board and the scope.

I think the 80psec minimum pulse width in the spec sheet is taken by calculating the time between the two points with half the maximum slope in the square edge response and this is not too different from the usual measurement of rise time. 40psec rise time may well be beyond the capability of these devices.

If anyone has the ability to design and populate a minimum PCB board for this chip it would be very useful, but I am sure it would not be a simple or low cost thing to do. Analog Devices used to sell the evaluation board for around $50 but the price went up a year or so back.

Roger


High Amplitude Pulse Generator - In Between Model?

Egge Siert
 

Hi to All,

Just received a "modern" version of the many times discussed High Amplitude Pulse Generator. This one has a dark green PWB with parts out of 1987 and a late style plastic front panel. The PN of the PWB is 671-0628. Intriging because the PN of the PG509 PWB is 671-0628-00. It has only four Op-Amps (two Dual) and not eight (two Dual and one Quad) as the PG509 has. It also has the lower Pre-Trigger Output Voltage in common with the later PG509. Maybe this model is the "attenuated" direct predecessor of the 067-1094-99?

I will make pictures of it and post them.

Greetings,

Egge Siert


Re: 067-0513-00 Pulse Generator

mosaicmerc
 

Ok, fair enough.

Postulation:
I feed the comparator a reasonably high impedance signal for its inverting input and a slightly higher level signal pulse on its non inverting input it produces a fast rise time logic high.
If I use a 45.4cm (30 cm x 100/65.9 to correct for signal propagation speeds) RG58 to feed back (from the output to the inverting input ) to cause the comparator to swing low I can generate a supposedly precise 1nS pulse (excluding Tr & Tf) via cable propagation delays.
The net propagation delay due to the comparator is then cancelled out. I can use different cable lengths to generate precise pulsewidth oscillations (excluding Tr & Tf) in the hundreds of Mhz to the Ghz range.

Can I then use a spectrum analyzer to sniff the harmonics and determine the true pulse lengths including the net rise & fall times and then derive the Tr & Tf, which happen to be about equal for this comparator?
I have a DSA 815-TG on hand.


Re: New to the group with a few questions

Tom Jobe <tomjobe@...>
 

Hello Leetmaster,
If you were able to remove the 3-48 set screw somehow, a 3/32 (.0935"
across the flats nominally) Allen wrench would not even fit into the
empty threaded hole, so something must be wrong with the details of what
you think you have.
In my very limited experience, Tektronix only used two small set screw
sizes on the control knobs and they use either a .050" or a 1/16"
(.0635" nominal size) Allen wrench.
The only small Allen wrenches i have seen that really work well are the
ones ground from solid tool steel that the radio control modelers use.
You can buy them at your local RC model shop, or online... I have done both.
The lesser Allen wrenches up through even the Whia and equivalent
premium brands are just not up to the job on the smaller size hex
wrenches in my experience.
tom jobe...


On 10/21/2015 1:08 PM, leetmaster4004@yahoo.com [TekScopes] wrote:

I did know that it can only go in the vertical slot. It looks like
they just re-purposed that button to turn off the output from the
module. That seems to be the sole functional difference between the
5CT1N and the 7.

An additional problem I forgot to bring up in my first post.


I picked up a 7D01 recently and am stripping it down to make some
repairs. I have two set screws that I can't find the correct size hex
wrench to remove. The manual states they are "SETSCREW :3-48 X 0 .095
INCH,HEX SOC STL"

3-48 is the set-screw size and thread spacing but I haven't been able
to find a hex wrench of size .095 inch. Has anyone come across the
right tool for these and if so where do I get one?

[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]


Re: 067-0513-00 Pulse Generator

 

Hi Ancel,

Avalanche generators have a limited repetition rate of a few hundred KHz. So
unless you were going to drive it with something like a 100KHz Xtal this
wouldn't be a good combination.

Generally, you don't see Avalanche mode or Tunnel Diode pulse generators
combined with crystal oscillators. I'm not sure exactly why that is. Current
mode switching logic driven by crystal oscillators is a better combination.
Current mode logic (CML) has few aberrations, fast rise and fall (30pSec),
and it outputs pulses that have flat tops and bottoms. CML can easily be
driven by a crystal oscillator of almost any frequency to make a time mark
generator.

Time-Mark Generators for scope calibration don't need high accuracy. Their
accuracy only needs to be 10X the most accurate sweep speed of your scope.
Most scopes have 1% to 2% sweep accuracy at best so a time base with 0.1% or
better accuracy will suffice. Tek made a nice, versatile Time-Mark Generator
- the 2901 - you can usually find for less than $100. It has a huge range of
time pulse outputs designed specifically for calibrating scopes and it is
crystal controlled for better than 0.001% accuracy.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 6:22 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Re: 067-0513-00 Pulse Generator

On Wed, 21 Oct 2015 19:00:04 -0400, you wrote:

Well with some spec sheet reading:
This looks useful:
http://www.farnell.com/datasheets/1903291.pdf
@$16 ea.

Feed it a logic signal and it will sharpen up the rise/fall to the sub
40 ps category with 50ohm termination built in. 400mV p-p 80ps min PW.

Questions I have:
1) Would this be a viable alt to the tunnel diode Tr bandwidth checking?
It will work find for bandwidth checking assuming that the pulse fidelity
shown in the datasheet can be maintained. That in itself may not be easy to
verify at high bandwidths without a sampling oscilloscope.

2) With an OXCO driven clk, would this be an alt to a time mark gen for
cal purposes?
A time mark generator for an analog oscilloscope does not need the accuracy
of an OXCO. A standard crystal is at least 20 times better than required.


------------------------------------
Posted by: David <davidwhess@gmail.com>
------------------------------------


------------------------------------

Yahoo Groups Links


Re: 067-0513-00 Pulse Generator

 

On Wed, 21 Oct 2015 19:00:04 -0400, you wrote:

Well with some spec sheet reading:
This looks useful:
http://www.farnell.com/datasheets/1903291.pdf
@$16 ea.

Feed it a logic signal and it will sharpen up the rise/fall to the sub
40 ps category with 50ohm termination built in. 400mV p-p
80ps min PW.

Questions I have:
1) Would this be a viable alt to the tunnel diode Tr bandwidth checking?
It will work find for bandwidth checking assuming that the pulse
fidelity shown in the datasheet can be maintained. That in itself may
not be easy to verify at high bandwidths without a sampling
oscilloscope.

2) With an OXCO driven clk, would this be an alt to a time mark gen for
cal purposes?
A time mark generator for an analog oscilloscope does not need the
accuracy of an OXCO. A standard crystal is at least 20 times better
than required.


Re: 2465B power supply - Sprague 290uF/200V big blue caps

vdonisa
 

Nope.

Look, there are millions of capacitors in use (for many decades now), in small signal coupling circuits, or in power AC applications, where they see little to no DC bias. Yet they fail to fail in a manner that could be attributed to the VDC/VDCmax ratio.

And, in the other corner, we have someone with an unproven allegation, shifting the burden of proof on everybody else to disprove his theory.

Well, there's also a teapot full of alien eggs orbiting Earth. Disprove that please. ;-)



---In TekScopes@yahoogroups.com, <david_wise@...> wrote :

I agree, but aren't you reversing your position?

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 4:59 PM
To: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

Not exactly. I'm saying that when trying to find a substitute cap, ESR, ripple current and thermal/size characteristics have priority over exactly matching voltage. Messing those has proven, well documented, dramatic effects. While "undervolting" doesn't.

In fact I'm not even original. Quote from another CDE document:

"Higher rated voltage capacitors may be substituted for lower rated voltage capacitors as long as case size, DF, and ESR ratings are also compatible."

(full document here: http://www.cde.com/resources/catalogs/AEappGUIDE.pdf http://www.cde.com/resources/catalogs/AEappGUIDE.pdf http://www.cde.com/resources/catalogs/AEappGUIDE.pdf http://www.cde.com/resources/catalogs/AEappGUIDE.pdf )


---In TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com, <david_wise@...> wrote :

I didn't. I remembered it wrong.

You're saying that with a 100V part, 1V is as good as 100V, are you?

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 3:44 PM
To: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

Where did you see the mention "near rated voltage"? It plainly says:

"In electrolytic capacitors, applying DC voltage actually drives a beneficial, on-going electrochemical reaction that heals defects in the anode dielectric."

Followed shortly by a description of the negative effects of simultaneously maxing out on both voltage and current/temperature.

---In TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com, <david_wise@...> wrote :

I read CDE_Multipliers.pdf, and they do claim that operating near rated voltage has the beneficial effect of repairing weak spots in the dielectric. Their graph of voltage life multipliers also stops at half of rated voltage.

I don't know how strongly this correlates with the useful life of a cap operated below rating. I suppose a graph would show a sweet spot with maximum life, with less at each end. I can't begin to guess at the shape of the tails.

The Shelf Life rating is based on storage at rated temperature. We don't know the degree to which thinning is accelerated by heat, although Arrhenius would be a reasonable first guess. A cap stored at comfortable room temperature will last much longer than the rating.

The Shelf Life test also applies rated voltage after storage. If the circuit applies only low voltage, this test will reject caps that operate just fine.

I just can't get righteous over this, but certainly there is *some* effect. We just don't know how much, and the people who research this for a living don't care about this operating point. I'm determined not to lose sleep over it.

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 12:29 PM
To: vdonisa@... mailto:vdonisa@... [TekScopes]
Subject: Re: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

On Tue, 20 Oct 2015, vdonisa@... mailto:vdonisa@... [TekScopes] wrote:

*PLONK*

>
> Thanks.
>
> I suggest in the future you also take it with Cornell Dubillier:
>
> https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1
>
> EPCOS/TDK:
>
> http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf
>
> and Illinois Capacitor:
>
> http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx
>
> to name just a few.
>
>







------------------------------------
Posted by: vdonisa@... mailto:vdonisa@...
------------------------------------


------------------------------------

Yahoo Groups Links







------------------------------------
Posted by: vdonisa@... mailto:vdonisa@...
------------------------------------


------------------------------------

Yahoo Groups Links


Re: 2465B power supply - Sprague 290uF/200V big blue caps

Dave Wise
 

I agree, but aren't you reversing your position?

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 4:59 PM
To: TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

Not exactly. I'm saying that when trying to find a substitute cap, ESR, ripple current and thermal/size characteristics have priority over exactly matching voltage. Messing those has proven, well documented, dramatic effects. While "undervolting" doesn't.

In fact I'm not even original. Quote from another CDE document:

"Higher rated voltage capacitors may be substituted for lower rated voltage capacitors as long as case size, DF, and ESR ratings are also compatible."

(full document here: http://www.cde.com/resources/catalogs/AEappGUIDE.pdf http://www.cde.com/resources/catalogs/AEappGUIDE.pdf )


---In TekScopes@yahoogroups.com, <david_wise@...> wrote :

I didn't. I remembered it wrong.

You're saying that with a 100V part, 1V is as good as 100V, are you?

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 3:44 PM
To: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

Where did you see the mention "near rated voltage"? It plainly says:

"In electrolytic capacitors, applying DC voltage actually drives a beneficial, on-going electrochemical reaction that heals defects in the anode dielectric."

Followed shortly by a description of the negative effects of simultaneously maxing out on both voltage and current/temperature.

---In TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com, <david_wise@...> wrote :

I read CDE_Multipliers.pdf, and they do claim that operating near rated voltage has the beneficial effect of repairing weak spots in the dielectric. Their graph of voltage life multipliers also stops at half of rated voltage.

I don't know how strongly this correlates with the useful life of a cap operated below rating. I suppose a graph would show a sweet spot with maximum life, with less at each end. I can't begin to guess at the shape of the tails.

The Shelf Life rating is based on storage at rated temperature. We don't know the degree to which thinning is accelerated by heat, although Arrhenius would be a reasonable first guess. A cap stored at comfortable room temperature will last much longer than the rating.

The Shelf Life test also applies rated voltage after storage. If the circuit applies only low voltage, this test will reject caps that operate just fine.

I just can't get righteous over this, but certainly there is *some* effect. We just don't know how much, and the people who research this for a living don't care about this operating point. I'm determined not to lose sleep over it.

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 12:29 PM
To: vdonisa@... mailto:vdonisa@... [TekScopes]
Subject: Re: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

On Tue, 20 Oct 2015, vdonisa@... mailto:vdonisa@... [TekScopes] wrote:

*PLONK*

>
> Thanks.
>
> I suggest in the future you also take it with Cornell Dubillier:
>
> https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1
>
> EPCOS/TDK:
>
> http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf
>
> and Illinois Capacitor:
>
> http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx
>
> to name just a few.
>
>







------------------------------------
Posted by: vdonisa@... mailto:vdonisa@...
------------------------------------


------------------------------------

Yahoo Groups Links



[Non-text portions of this message have been removed]



------------------------------------
Posted by: vdonisa@yahoo.com
------------------------------------


------------------------------------

Yahoo Groups Links


Re: 2465B power supply - Sprague 290uF/200V big blue caps

vdonisa
 

Not exactly. I'm saying that when trying to find a substitute cap, ESR, ripple current and thermal/size characteristics have priority over exactly matching voltage. Messing those has proven, well documented, dramatic effects. While "undervolting" doesn't.

In fact I'm not even original. Quote from another CDE document:

"Higher rated voltage capacitors may be substituted for lower rated voltage capacitors as long as case size, DF, and ESR ratings are also compatible."

(full document here: http://www.cde.com/resources/catalogs/AEappGUIDE.pdf http://www.cde.com/resources/catalogs/AEappGUIDE.pdf )


---In TekScopes@yahoogroups.com, <david_wise@...> wrote :

I didn't. I remembered it wrong.

You're saying that with a 100V part, 1V is as good as 100V, are you?

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 3:44 PM
To: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

Where did you see the mention "near rated voltage"? It plainly says:

"In electrolytic capacitors, applying DC voltage actually drives a beneficial, on-going electrochemical reaction that heals defects in the anode dielectric."

Followed shortly by a description of the negative effects of simultaneously maxing out on both voltage and current/temperature.

---In TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com, <david_wise@...> wrote :

I read CDE_Multipliers.pdf, and they do claim that operating near rated voltage has the beneficial effect of repairing weak spots in the dielectric. Their graph of voltage life multipliers also stops at half of rated voltage.

I don't know how strongly this correlates with the useful life of a cap operated below rating. I suppose a graph would show a sweet spot with maximum life, with less at each end. I can't begin to guess at the shape of the tails.

The Shelf Life rating is based on storage at rated temperature. We don't know the degree to which thinning is accelerated by heat, although Arrhenius would be a reasonable first guess. A cap stored at comfortable room temperature will last much longer than the rating.

The Shelf Life test also applies rated voltage after storage. If the circuit applies only low voltage, this test will reject caps that operate just fine.

I just can't get righteous over this, but certainly there is *some* effect. We just don't know how much, and the people who research this for a living don't care about this operating point. I'm determined not to lose sleep over it.

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 12:29 PM
To: vdonisa@... mailto:vdonisa@... [TekScopes]
Subject: Re: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

On Tue, 20 Oct 2015, vdonisa@... mailto:vdonisa@... [TekScopes] wrote:

*PLONK*

>
> Thanks.
>
> I suggest in the future you also take it with Cornell Dubillier:
>
> https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1
>
> EPCOS/TDK:
>
> http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf
>
> and Illinois Capacitor:
>
> http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx
>
> to name just a few.
>
>







------------------------------------
Posted by: vdonisa@... mailto:vdonisa@...
------------------------------------


------------------------------------

Yahoo Groups Links


Re: 067-0513-00 Pulse Generator

 

What is needed to get rise times faster than 100 picoseconds with an
avalanche pulse generator?

Is all surface mount construction sufficient? I suspect the lead
inductance is the major limitation. A transistor with dual leads on
the collector and emitter would be handy for this.

I am not impressed with the aberrations of the avalanche pulse
generator design at the silionvalleygarage link. If I went this
route, I would try adding a diode disconnect circuit which is common
in flat level pulse generators.

On Wed, 21 Oct 2015 13:31:18 -0700, you wrote:

Hi Roger,
As you point out avalanche transistor pulsers are incredibly simple to
build. Almost any transistor will work, and a short piece of coax is all you
need to stretch the pulse. Plus they generate a lot of voltage (unlike TDs)
which in some cases is a plus. Early in my career I built one and was really
impressed at the results.

If you are very careful you can get rise times under 30pSec. But generally
speaking it takes a good sampler to be able to measure those kinds of edge
speeds. Somewhere about a year ago on the internet I came across somebody
that published the test results of the avalanche speeds he measured of about
15 0r 20 transistors. They were all pretty fast but some were incredible. I
wish I could remember where I saw that list.

Dennis Tillman W7PF


Re: 2465B power supply - Sprague 290uF/200V big blue caps

Dave Wise
 

I didn't. I remembered it wrong.

You're saying that with a 100V part, 1V is as good as 100V, are you?

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 3:44 PM
To: TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

Where did you see the mention "near rated voltage"? It plainly says:

"In electrolytic capacitors, applying DC voltage actually drives a beneficial, on-going electrochemical reaction that heals defects in the anode dielectric."

Followed shortly by a description of the negative effects of simultaneously maxing out on both voltage and current/temperature.

---In TekScopes@yahoogroups.com, <david_wise@...> wrote :

I read CDE_Multipliers.pdf, and they do claim that operating near rated voltage has the beneficial effect of repairing weak spots in the dielectric. Their graph of voltage life multipliers also stops at half of rated voltage.

I don't know how strongly this correlates with the useful life of a cap operated below rating. I suppose a graph would show a sweet spot with maximum life, with less at each end. I can't begin to guess at the shape of the tails.

The Shelf Life rating is based on storage at rated temperature. We don't know the degree to which thinning is accelerated by heat, although Arrhenius would be a reasonable first guess. A cap stored at comfortable room temperature will last much longer than the rating.

The Shelf Life test also applies rated voltage after storage. If the circuit applies only low voltage, this test will reject caps that operate just fine.

I just can't get righteous over this, but certainly there is *some* effect. We just don't know how much, and the people who research this for a living don't care about this operating point. I'm determined not to lose sleep over it.

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 12:29 PM
To: vdonisa@... mailto:vdonisa@... [TekScopes]
Subject: Re: [TekScopes] Re: 2465B power supply - Sprague 290uF/200V big blue caps

On Tue, 20 Oct 2015, vdonisa@... mailto:vdonisa@... [TekScopes] wrote:

*PLONK*

>
> Thanks.
>
> I suggest in the future you also take it with Cornell Dubillier:
>
> https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1 https://www.digikey.com/Web%20Export/Supplier%20Content/CDE_338/PDF/CDE_Multipliers.pdf?redirected=1
>
> EPCOS/TDK:
>
> http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf http://en.tdk.eu/designtools/alu_useful_life/Useful_life.swf
>
> and Illinois Capacitor:
>
> http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx
>
> to name just a few.
>
>







------------------------------------
Posted by: vdonisa@yahoo.com
------------------------------------


------------------------------------

Yahoo Groups Links


Re: 067-0513-00 Pulse Generator

mosaicmerc
 

Well with some spec sheet reading:
This looks useful:
http://www.farnell.com/datasheets/1903291.pdf
@$16 ea.

Feed it a logic signal and it will sharpen up the rise/fall to the sub 40 ps category with 50ohm termination built in. 400mV p-p
80ps min PW.

Questions I have:
1) Would this be a viable alt to the tunnel diode Tr bandwidth checking?
2) With an OXCO driven clk, would this be an alt to a time mark gen for cal purposes?


Re: 2465B power supply - Sprague 290uF/200V big blue caps

vdonisa
 

Where did you see the mention "near rated voltage"? It plainly says:

"In electrolytic capacitors, applying DC voltage actually drives a beneficial, on-going electrochemical reaction that heals defects in the anode dielectric."

Followed shortly by a description of the negative effects of simultaneously maxing out on both voltage and current/temperature.

---In TekScopes@yahoogroups.com, <david_wise@...> wrote :

I read CDE_Multipliers.pdf, and they do claim that operating near rated voltage has the beneficial effect of repairing weak spots in the dielectric. Their graph of voltage life multipliers also stops at half of rated voltage.

I don't know how strongly this correlates with the useful life of a cap operated below rating. I suppose a graph would show a sweet spot with maximum life, with less at each end. I can't begin to guess at the shape of the tails.

The Shelf Life rating is based on storage at rated temperature. We don't know the degree to which thinning is accelerated by heat, although Arrhenius would be a reasonable first guess. A cap stored at comfortable room temperature will last much longer than the rating.

The Shelf Life test also applies rated voltage after storage. If the circuit applies only low voltage, this test will reject caps that operate just fine.

I just can't get righteous over this, but certainly there is *some* effect. We just don't know how much, and the people who research this for a living don't care about this operating point. I'm determined not to lose sleep over it.

Dave Wise


Sold ( FS: assorted Tektronix PC boards)

Brad Thompson <brad.thompson@...>
 

Hello--

My thanks go to everyone who inquired.

73--

Brad AA1IP


Re: 067-0513-00 Pulse Generator

Brad Thompson <brad.thompson@...>
 

On 10/21/2015 4:31 PM, 'Dennis Tillman' dennis@ridesoft.com [TekScopes] wrote:

<snip> Somewhere about a year ago on the internet I came across somebody
that published the test results of the avalanche speeds he measured of about
15 0r 20 transistors. They were all pretty fast but some were incredible. I
wish I could remember where I saw that list.
Hello--

I couldn't locate that list either, but I stumbled across this paper...

"Nanosecond switching of power MOSFET" in which the authors use a 2N3904 in avalanche mode
to charge a MOSFET's gate capacitance really quickly:

cmosedu.com/jbaker/papers/1990/RSI81990.pdf

...Which was intriguing enough to call to the group's attention.
73--

Brad AA1IP


Re: New to the group with a few questions

James
 

The display button is just fine for me as while I've been learning the equipment its been helpful to have a no questions asked simple OFF button on a module. My 7613 doesn't have em but everything I find says the 7000's are the bigger badder brother of the 5000's so they probably need the space for more important things.

I'm in the US though my default measurement system is metric from my IT background. My first problem was assuming metric till I was reminded that this equipment was made during in the US during the cold war so "standard" was the way to go.


I'll dig up a 3/32 hex wrench and see how that goes though I've had a bad feeling that the two setscrews are stripped as all the rest of the modules I am rebuilding have had the right feel when I was removing the setscrews. I work with Apple products from time to time so I am well versed in unreasonably tight tolerances and these two setscrews haven't been right since day one.


If they are indeed stripped any advice on further removal methods? I've never found a proper bit small enough for removing stripped laptop screws which are usually bigger than one of these.


Re: 067-0513-00 Pulse Generator

 

Hi David,
I looked at that same picture and decided it was a strange way the scope calculated the risetime. First, I think the scope picked the lowest point of the pulse (just prior to the rise the pulse baseline was nice and flat so that was easy) and it picked the highest point of the pules which was right before the pulse ended.

Then it looks like it chose the 20% and 80% points to determine the risetime. Tek normally uses the 10% and 90% points and they only look at the height of the rising edge.

Finally, this scope is supposed to be ultra-ultra-fast (according to him) so why didn't he take a screen shot of the rising edge alone at a faster sweep speed so we could see what the edge rise time was and what the rising edge actually looked like.

I'm still left with the impression he is trying to play down the negative aspects of his little pulser.

Over the years several other people have attempted to make and sell pocket size pulsers based on avalanche mode transistors but none has met with any commercial success. They are a tough sell. Maybe he will be the first.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 1:41 PM
Cc: TekScopes <TekScopes@yahoogroups.com>
Subject: Re: [TekScopes] Re: 067-0513-00 Pulse Generator

On Wed, Oct 21, 2015 at 2:24 PM, Dennis Tillman <dennis@ridesoft.com> wrote:

It is a cute little packaging job. But the most important information of all, the risetime, seems to be suspiciously missing from his writeup. He talks up this incredibly fast scope but the scope photo he includes makes it hard to tell the risetime of the pulse. It is as if he seems to have intentionally obfuscated the actual results. I agree with David that the rising edge doesn't look all that fast.
The screen shot at the end says 200ps:
http://www.siliconvalleygarage.com/_Media/screen-shot-2013-11-24-at_med.png

------------------------------------
Posted by: David DiGiacomo <telists@davmar.org>
------------------------------------


Re: New to the group with a few questions

 

Hi Lee,
Yes, that is the way the entire 5000 series works. Personally I have always
thought that the DISPLAY button at the top of 5000 series plugins is weird.
But since I did not have to deal with the design problems the engineers were
confronted with when they created these products it is a cheap shot on my
part when I call their choices weird.

Since on the internet it is impossible to know where you are I am going to
guess you are in one of those intelligent countries that has adopted the
metric system. The set screws Tek used are designed for the "other" system
(the English system) that uses inches. The nice thing about changing set
screws in Tek knobs is that there are only two sizes of hex wrench you need.
Buy a set of non-metric hex wrenches and you will be able to remove the set
screws. Don't try removing them with a metric hex wrench or you will strip
the head and then you are in real trouble.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, October 21, 2015 1:08 PM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] Re: New to the group with a few questions

I did know that it can only go in the vertical slot. It looks like they just
re-purposed that button to turn off the output from the module. That seems
to be the sole functional difference between the 5CT1N and the 7.

An additional problem I forgot to bring up in my first post.

I picked up a 7D01 recently and am stripping it down to make some repairs.
I have two set screws that I can't find the correct size hex wrench to
remove. The manual states they are "SETSCREW :3-48 X 0 .095 INCH,HEX SOC
STL"

3-48 is the set-screw size and thread spacing but I haven't been able to
find a hex wrench of size .095 inch. Has anyone come across the right tool
for these and if so where do I get one?

------------------------------------
Posted by: leetmaster4004@yahoo.com
------------------------------------

73041 - 73060 of 192872