BNC protector caps - Page 1
Forum section: electronics / testgear

author: joeqsmith
author_rank: Super Contributor
timestamp: January 24, 2025, 04:15:23 pm
content: https://www.eevblog.com/forum/testgear/new-rigol-16-bit-function-generators-dg800900-series/msg3348094/#msg3348094One 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.

author: Martin72
author_rank: Super Contributor
timestamp: January 24, 2025, 04:27:33 pm
content: 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

author: tooki
author_rank: Super Contributor
timestamp: January 24, 2025, 04:30:22 pm
content: 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, butshorting 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.

author: tooki
author_rank: Super Contributor
timestamp: January 24, 2025, 04:33:51 pm
content: P.S. Not to mention this risk of using shorting plugs as caps: what if you dead short anoutputconnector?!

author: squadchannel
author_rank: Frequent Contributor
timestamp: January 24, 2025, 04:35:33 pm
content: it is not protector cap. its shorting cap.

author: 2N3055
author_rank: Super Contributor
timestamp: January 24, 2025, 04:50:18 pm
content: Ouch.That BNC is demolished...

author: Martin72
author_rank: Super Contributor
timestamp: January 24, 2025, 05:04:39 pm
content: I would rather build such a short-circuit cap myself with a good BNC plug, then nothing will happen.

author: tooki
author_rank: Super Contributor
timestamp: January 24, 2025, 05:15:43 pm
content: How is that better than just buying a shorting plug from one of the good manufacturers?

author: nctnico
author_rank: Super Contributor
timestamp: January 24, 2025, 05:57:34 pm
content: I like these:https://aliexpress.com/item/4001286556507.htmlEither 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.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 24, 2025, 06:07:43 pm
content: 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.

author: calibrationfixture
author_rank: Regular Contributor
timestamp: January 24, 2025, 06:21:22 pm
content: Hi to All,I use these:https://www.ebay.com/itm/121430859080Calibrationfixture

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 24, 2025, 07:08:16 pm
content: Quote from: calibrationfixture on January 24, 2025, 06:21:22 pm

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 24, 2025, 07:10:39 pm
content: Quote from: BILLPOD on January 24, 2025, 07:08:16 pm

author: Zoli
author_rank: Frequent Contributor
timestamp: January 24, 2025, 07:27:41 pm
content: For whoever is interested, the yellow plugs are most likely Caplugs EP-8. For the whole menu, visit the Caplugs website.

author: factory
author_rank: Super Contributor
timestamp: January 24, 2025, 07:30:29 pm
content: Quote from: joeqsmith on January 24, 2025, 06:07:43 pmMouser sell Caplugs EP-8 (yellow), SEP-08 (Static Dissipative pink) and CEP-08 (Conductive black) in quantities of 1 or more.David

author: Hydron
author_rank: Super Contributor
timestamp: January 24, 2025, 08:01:37 pm
content: 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.

author: Martin72
author_rank: Super Contributor
timestamp: January 24, 2025, 08:15:06 pm
content: Quote from: tooki on January 24, 2025, 05:15:43 pmI didn't write that it was better.I just wrote that I would do it that way.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 24, 2025, 09:26:07 pm
content: 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.

author: Martin72
author_rank: Super Contributor
timestamp: January 24, 2025, 09:49:43 pm
content: QuoteThis 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.

author: nctnico
author_rank: Super Contributor
timestamp: January 25, 2025, 12:56:43 am
content: Quote from: Martin72 on January 24, 2025, 09:49:43 pmThat 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

author: joeqsmith
author_rank: Super Contributor
timestamp: January 25, 2025, 02:21:12 am
content: As mentioned, most of my TE would have no problems with shorting their outputs. This one is a special case.

author: factory
author_rank: Super Contributor
timestamp: January 25, 2025, 01:31:26 pm
content: Quote from: joeqsmith on January 24, 2025, 09:26:07 pmThere is only one "P" in Caplugs, might help with finding alternate suppliersifdigikey don't have them and you don't use Mouser.https://www.caplugs.com/David

author: joeqsmith
author_rank: Super Contributor
timestamp: January 25, 2025, 04:42:03 pm
content: Quote from: factory on January 25, 2025, 01:31:26 pmWhen using Digi-key, it's easy enough to see who are their suppliers. For a wider search, Google has the spelling covered.

author: mawyatt
author_rank: Super Contributor
timestamp: January 25, 2025, 05:09:29 pm
content: Quote from: joeqsmith on January 25, 2025, 02:21:12 amThat 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 yearshttps://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

author: joeqsmith
author_rank: Super Contributor
timestamp: January 25, 2025, 07:53:08 pm
content: 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/

author: Stray Electron
author_rank: Super Contributor
timestamp: January 25, 2025, 08:03:18 pm
content: Quote from: calibrationfixture on January 24, 2025, 06:21:22 pmX2. I bought a pack of 100 of these from Ebay for something like $12 a couple of years ago. Now I don't have to worry about losing one of the metal caps or not having enough caps for ALL of my TE.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 26, 2025, 02:35:22 am
content: Not sure this shows you what you are looking for but here you go. Details about my 35 year old homemade arb.

author: mawyatt
author_rank: Super Contributor
timestamp: January 26, 2025, 04:05:09 am
content: Great video!! Thanks!!Impressive documentation and design, the wire wrap brings back fond memoriesNeat idea using a scanner to input a hand drawn waveform!!Best

author: tooki
author_rank: Super Contributor
timestamp: January 26, 2025, 11:50:53 am
content: Quote from: Martin72 on January 24, 2025, 08:15:06 pmWhich means there is a reason you’d do that instead of just buying one. What is that reason?

author: 2N3055
author_rank: Super Contributor
timestamp: January 26, 2025, 02:02:34 pm
content: Quote from: tooki on January 26, 2025, 11:50:53 amOne reason would be that you might have many BNC connectors in store already.... And if you only need few shorted ones it is faster and easier just to make a few..

author: joeqsmith
author_rank: Super Contributor
timestamp: January 27, 2025, 01:50:51 am
content: Quote from: Martin72 on January 24, 2025, 04:27:33 pmThanks. Found them with and without the chain. This is really what I was after.

author: 5U4GB
author_rank: Super Contributor
timestamp: January 27, 2025, 09:46:53 am
content: Quote from: nctnico on January 24, 2025, 05:57:34 pmBeat me to it, I use translucent/whiteish ones of a similar design, you can buy a lifetime's supply off Aliexpress for a few dollars.

author: Neoname
author_rank: Contributor
timestamp: January 27, 2025, 04:40:17 pm
content: I use Molex 73415-1961 dust caps, but the current price is several multiples of what I paid some years ago. They're reliable, cause no damage and I have no problem with them.Datasheet ishereandhere.

author: joeqsmith
author_rank: Super Contributor
timestamp: February 02, 2025, 02:57:10 am
content: I took a few photos of the documentation for the DC coupled power amplifier. The 1N4004, 2N4401/03 were my goto parts of the time.Schematics would have been in Orcad for DOS. 800x600 res. SPICE would have been PSPICE for DOS. Guessing documents were written in WordStar.You can find a scanned copy of that 1990 HP catalog I show here. Look at what Arbs were available back then.http://hparchive.com/Catalogs/HP-Catalog-1990.pdfSomeone asked about why such a need for a low impedance power driver. I don't normally discuss work topics in public forums but I was working on a project that was using something like an LVDT sensor and we were needing to drive it with a odd waveform. A few co-engineers got to play with it. As useful as it was, we did not go into the the Arb business.