Author Topic: BNC protector caps  (Read 1871 times)

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Offline joeqsmithTopic starter

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BNC protector caps
« on: January 24, 2025, 04:15:23 pm »
https://www.eevblog.com/forum/testgear/new-rigol-16-bit-function-generators-dg800900-series/msg3348094/#msg3348094

One out of ten was not crimped causing it to be out of center.  Shown what happened when connecting it to BNC.   

Personally, I would rather they ditch the pin and make the rubber seal without the hole.

Online Martin72

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Re: BNC protector caps
« Reply #1 on: January 24, 2025, 04:27:33 pm »
That's why I have some without a center pin, which you don't need if you just want to protect the jacks from dust.
Amazon
« Last Edit: January 24, 2025, 04:29:57 pm by Martin72 »
 
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Offline tooki

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Re: BNC protector caps
« Reply #2 on: January 24, 2025, 04:30:22 pm »
How bizarre. All the BNC protective caps I’ve ever seen so far are exactly what you wish for: a rubber surface inside and that’s it. (Edit: exactly like in Martin72’s photos.) A protective cap has no need for a pin, and it seems like an added cost!

I suspect that the caps you have weren’t designed to be protective caps, but shorting plugs. (0 ohm terminators, so to speak.) Those definitely exist, too. I’d never use one as a substitute for a basic cap, though! (Why wear out the jack’s female contact when not needed?)

Of course, the existence of shorting plugs doesn’t excuse the shoddy manufacturing of the ones you got.
« Last Edit: January 24, 2025, 04:32:29 pm by tooki »
 

Offline tooki

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Re: BNC protector caps
« Reply #3 on: January 24, 2025, 04:33:51 pm »
P.S. Not to mention this risk of using shorting plugs as caps: what if you dead short an output connector?!
 

Online squadchannel

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Re: BNC protector caps
« Reply #4 on: January 24, 2025, 04:35:33 pm »
it is not protector cap. its shorting cap.
 
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Offline 2N3055

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Re: BNC protector caps
« Reply #5 on: January 24, 2025, 04:50:18 pm »
Ouch.
That BNC is demolished...
"Just hard work is not enough - it must be applied sensibly."
Dr. Richard W. Hamming
 

Online Martin72

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Re: BNC protector caps
« Reply #6 on: January 24, 2025, 05:04:39 pm »
I would rather build such a short-circuit cap myself with a good BNC plug, then nothing will happen.

Offline tooki

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Re: BNC protector caps
« Reply #7 on: January 24, 2025, 05:15:43 pm »
How is that better than just buying a shorting plug from one of the good manufacturers?
 
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Offline nctnico

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Re: BNC protector caps
« Reply #8 on: January 24, 2025, 05:57:34 pm »
I like these:

https://aliexpress.com/item/4001286556507.html



Either way I'd go for a cap without a center pin. Especially when the cap is cheap; it will do more harm than good if it has a pin.
« Last Edit: January 24, 2025, 06:00:17 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline joeqsmithTopic starter

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Re: BNC protector caps
« Reply #9 on: January 24, 2025, 06:07:43 pm »
I use CapPlugs for most of my equipment.  I can get them with ESD plastic.   The problem is they don't offer them in low quantities. 

Offline calibrationfixture

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Re: BNC protector caps
« Reply #10 on: January 24, 2025, 06:21:22 pm »
Hi to All,

I use these:

https://www.ebay.com/itm/121430859080

Calibrationfixture
« Last Edit: January 24, 2025, 06:26:16 pm by calibrationfixture »
 

Offline BILLPOD

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Re: BNC protector caps
« Reply #11 on: January 24, 2025, 07:08:16 pm »
 

Offline BILLPOD

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Re: BNC protector caps
« Reply #12 on: January 24, 2025, 07:10:39 pm »
Hi to All,

I use these:

https://www.ebay.com/itm/121430859080
OOPS, I forgot to comment that I don't need 250 of the yellow caps.
Calibrationfixture
 

Online Zoli

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Re: BNC protector caps
« Reply #13 on: January 24, 2025, 07:27:41 pm »
For whoever is interested, the yellow plugs are most likely Caplugs EP-8. For the whole menu, visit the Caplugs website.
 

Offline factory

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Re: BNC protector caps
« Reply #14 on: January 24, 2025, 07:30:29 pm »
I use CapPlugs for most of my equipment.  I can get them with ESD plastic.   The problem is they don't offer them in low quantities.

Mouser sell Caplugs EP-8 (yellow), SEP-08 (Static Dissipative pink) and CEP-08 (Conductive black) in quantities of 1 or more.

David
 
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Offline Hydron

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Re: BNC protector caps
« Reply #15 on: January 24, 2025, 08:01:37 pm »
The ones with just the rubber bit are cheaper than the shorting ones to boot! I don't bother with them for BNCs but do use them for triax connectors.
 

Online Martin72

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Re: BNC protector caps
« Reply #16 on: January 24, 2025, 08:15:06 pm »
How is that better than just buying a shorting plug from one of the good manufacturers?

I didn't write that it was better.
I just wrote that I would do it that way.

Offline joeqsmithTopic starter

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Re: BNC protector caps
« Reply #17 on: January 24, 2025, 09:26:07 pm »
I did check Digi-key but they do not appear to carry CapPlug.   I ordered ones like Martin linked without the pin, with and without the chain.   Thinking it may be possible to use the chain with the LeCroy scopes.   

As far as shorting the outputs,  most of my TE is will not be damaged from it.  They are mostly small signal, 50 ohm.   I do have some home made devices I would not want to short,  power amplifiers, Arb...  More to the point, I don't have any reason to ever short a BNC.

Online Martin72

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Re: BNC protector caps
« Reply #18 on: January 24, 2025, 09:49:43 pm »
Quote
More to the point, I don't have any reason to ever short a BNC.

This is sometimes done to minimize the influence of external noise when measuring the intrinsic noise(input shorted to ground).
With oscilloscopes, however, this would be unnecessary because most of them can be switched to GND in the channel menu.

Offline nctnico

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Re: BNC protector caps
« Reply #19 on: January 25, 2025, 12:56:43 am »
Quote
More to the point, I don't have any reason to ever short a BNC.

This is sometimes done to minimize the influence of external noise when measuring the intrinsic noise(input shorted to ground).
With oscilloscopes, however, this would be unnecessary because most of them can be switched to GND in the channel menu.
That doesn't always work because some scopes substitute the ADC output with zero when switched to GND resulting in a perfectly flat line.

Edit: typo
« Last Edit: January 25, 2025, 01:50:37 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline joeqsmithTopic starter

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Re: BNC protector caps
« Reply #20 on: January 25, 2025, 02:21:12 am »
As mentioned, most of my TE would have no problems with shorting their outputs.   This one is a special case.


Offline factory

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Re: BNC protector caps
« Reply #21 on: January 25, 2025, 01:31:26 pm »
I did check Digi-key but they do not appear to carry CapPlug.   I ordered ones like Martin linked without the pin, with and without the chain.   Thinking it may be possible to use the chain with the LeCroy scopes.   

As far as shorting the outputs,  most of my TE is will not be damaged from it.  They are mostly small signal, 50 ohm.   I do have some home made devices I would not want to short,  power amplifiers, Arb...  More to the point, I don't have any reason to ever short a BNC.

There is only one "P" in Caplugs, might help with finding alternate suppliers if digikey don't have them and you don't use Mouser.
https://www.caplugs.com/

David
 

Offline joeqsmithTopic starter

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Re: BNC protector caps
« Reply #22 on: January 25, 2025, 04:42:03 pm »
I did check Digi-key but they do not appear to carry CapPlug.   I ordered ones like Martin linked without the pin, with and without the chain.   Thinking it may be possible to use the chain with the LeCroy scopes.   

As far as shorting the outputs,  most of my TE is will not be damaged from it.  They are mostly small signal, 50 ohm.   I do have some home made devices I would not want to short,  power amplifiers, Arb...  More to the point, I don't have any reason to ever short a BNC.

There is only one "P" in Caplugs, might help with finding alternate suppliers if digikey don't have them and you don't use Mouser.
https://www.caplugs.com/

David

When using Digi-key,  it's easy enough to see who are their suppliers.  For a wider search, Google has the spelling covered.

Offline mawyatt

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Re: BNC protector caps
« Reply #23 on: January 25, 2025, 05:09:29 pm »
As mentioned, most of my TE would have no problems with shorting their outputs.   This one is a special case.



That home brew high current AWG looks interesting, maybe open a thread on such.

We've been up against the typical AWG limits on Power/Current/Voltage a few times and decided to add a couple external (inexpensive) augmenting buffer amps to our standard AWGs. These have proved quite useful over the years :-+

https://www.eevblog.com/forum/testgear/cheap-diy-high-powervoltage-awg-buffer-amp/

https://www.eevblog.com/forum/testgear/hv-buffer-amp-for-awg/

https://www.eevblog.com/forum/testgear/hv-buffer-amp-for-awg/

BTW at one point some time ago we were contemplating developing a AWG Buffer DC Coupled Amp that could supply ~10amps but never got around to this, it was to drive motors/solenoids and such.

Best
« Last Edit: January 25, 2025, 05:22:52 pm by mawyatt »
Curiosity killed the cat, also depleted my wallet!
~Wyatt Labs by Mike~
 

Offline joeqsmithTopic starter

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Re: BNC protector caps
« Reply #24 on: January 25, 2025, 07:53:08 pm »
Sure, I can do some sort of tear down and go over  the design.  Just keep in mind that arb is a 30+ year old relic, homemade, hobby project for fun.   

I mentioned that Techron amplifier to you.   They make high powered DC coupled products for industrial use.   
https://aetechron.com/product-category/amplifiers/


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