probes cables bnc connectors clips hooks and all else I should get. - Page 1
Forum section: electronics / beginners

author: AcousticBruce
author_rank: Contributor
timestamp: April 11, 2013, 09:11:01 pm
content: So I have all these...-LeCroy 200mhz la303-Lodestar Function Generator-HP8601 timer-HP Generator Sweeper-BK Precision DC Benchtop Supply-Fluke 83IIIAND only 2 oscilloscope probes and black and red fluke point probesMy question is about supplies I need to buy. What kind of connector, probes, clips, and other s0ecial ite.s should I get so I can start using timers generators and sweepers?This is a awesome vid that I would like to replicate.

author: w2aew
author_rank: Super Contributor
timestamp: April 11, 2013, 09:26:18 pm
content: Hey - that video looks familiar!Start off with a good selection of:BNC-BNC cablesBNC - mini-clip adaptersBNC - banana adaptersBanana - Banana leads that are "stackable"Banana - mini-clip leadsBanana - alligator clip leadsAlligator - Alligator leadsBNC 50ohm feedthrough terminationsBNC DC Blocksetc.Even when you build up a nice collection, you'll always find yourself needing one more adapter, cable, lead or probe... So, when you run into that situation, jot down a little note of what you needed, so you can refer to it later when "shopping" at a hamfest or flea market...

author: AcousticBruce
author_rank: Contributor
timestamp: April 12, 2013, 02:01:24 am
content: Yes!!! Dude you make the most interesting videos. Thank you so much for your help with the tools needed.I have a video request. I would like to understand all the uses of isolated transformers. What do you think?

author: w2aew
author_rank: Super Contributor
timestamp: April 12, 2013, 02:40:02 am
content: Isolated transformers? Or, isolation transformers? What is the context or application that your are running across these transformers?

author: senso
author_rank: Frequent Contributor
timestamp: April 12, 2013, 02:57:29 am
content: And for those that don't have the pleasure of having hamfests or fleamarkets, what is the most cost effective solution to acquire a nice collection of cables?I have bough a pair of pomona mini grabers, and a DMM basic test lead set, and that cost me 44€, and it will get way too expensive fast, and something says me that cables from ebay will be miserable

author: w2aew
author_rank: Super Contributor
timestamp: April 12, 2013, 04:20:43 am
content: Are there any local ham radio clubs in your area? They might have better local advice than I could possibly give you.

author: smashedProton
author_rank: Frequent Contributor
timestamp: April 12, 2013, 02:27:34 pm
content: Robrenz's kelvin clips are really nice. I wish that I had a shop like that haha

author: Resistoid
author_rank: Contributor
timestamp: April 13, 2013, 09:54:10 pm
content: Senso, a potential solution is to buy various types of connectors and reels of cable to make your own. - This is what I've been doing for years.Resistoid.

author: AcousticBruce
author_rank: Contributor
timestamp: April 15, 2013, 02:51:05 am
content: Quote from: w2aew on April 12, 2013, 02:40:02 amWell let me tell you this short story first... this is where the question derived from anyway. I made a power supply with my computers (desktop pc) old switchmode power supply back when I was first trying to make a lab. I got my proto board and created little circuits with small voltage. When measuring with the scope I shorted out numerous times with the scopes ground clip. This was because I did not understand about ground. I was told by a forum that I should get a isolated transformer and plug the power supply into it. Well now I have a BK Precision bench-top 0-30V and it has - + and earth ground. So this power supply is different.So my question is stemming from not knowing how to properly set up a breadboard and small op amp circuits for testing. Would I need to use a isolated transformer? I know my BK Precision 1635 has Isolated Outputs and either polarity my be floating or grounded (which is much better than the desktop PS hack). So when is a isolated transformer used for testing? I do not know the difference between a "isolated transformer" and a "isolation transformer".So really I guess I would rather request a video on setting up various breadboard circuits for testing. How to use the scope and other meters. Using words like: isolation, grounded, floating, earth ground. How and why would I use positive and negative rails and make them floating or grounded?... things like that.I have watched the famous "how to not blow up your oscilloscope" by David (mr. EEVBlog himself) It was very helpful. I just would really like to see a video from you explaining how to test and learn from circuits.Your oscilloscope series is wonderful. I watched them all. I really feel like I am pretty good at scopes and their functions.Quote from: Resistoid on April 13, 2013, 09:54:10 pmActually when I saw that I can easily spend a couple hundred on these things I thought about this. Perhaps the crimping tools are worth buying. This may be an option.

author: Resistoid
author_rank: Contributor
timestamp: April 15, 2013, 11:50:17 am
content: AcousticBruce, youmaynot even need anything as "specialised" as crimping tools. - There are loads of cables / connectors you can prepare with a soldering iron. Actually, I've not had to crimp a cable yet in the relatively simple stuff I tinker with. Not that it would hurt to have the option of crimping...Resistoid.

author: casinada
author_rank: Frequent Contributor
timestamp: April 15, 2013, 04:12:52 pm
content: Just be patient and you can score new old stock Pomona, Tektronix, Mueller, Minicircuits connectors, adapters, coax, etc on ebay. As Scope Guru w2aew said there is not such a thing as enough cablesand as others might add, there is not such a thing as enough tools. My wife would add there is no such a thing as enough shoes

author: w2aew
author_rank: Super Contributor
timestamp: April 15, 2013, 05:31:15 pm
content: OK, what you were really looking for was an isolation transformer (not an isolated transformer). This gives you galvanic isolation between the load and the mains ground. They were very popular back in the days before grounded plugs, and the the chassis of any given piece of electrical gear could be "hot" with respect to the test gear's ground. Nowadays, it is much more common to get yourself a proper bench supply that features floating outputs - this is where the ground terminal is isolated from the + and - terminals of the supply output - thus it lets you tie the ground to either of the supply terminals (or neither), depending on the needs/design of your circuit. So, save your money on the isolation transformer, and save a little more and pick up a proper bench supply. That will ultimately be more useful to you than the isolation transformer.

author: grego
author_rank: Frequent Contributor
timestamp: April 15, 2013, 07:47:32 pm
content: Quote from: w2aew on April 11, 2013, 09:26:18 pmHoly cow BNC feedthrough terminations are expensive. $42 from digikey. Zoikes! I never knew!

author: Unknown
author_rank: Unknown
timestamp: April 15, 2013, 08:32:12 pm
content: Yes, feed-through terminators are insanely expensive, probably because of limited demand. In general, connectors, adapters and cables are quite expensive, especially if you add it all up. It's not hard to spend a few hundred USD on this stuff.

author: Resistoid
author_rank: Contributor
timestamp: April 15, 2013, 09:53:46 pm
content: Jim Williams made apposite comments on the price of the hardware:"Finally, cables, connectors, and adapters are a must have. You need a wide variety of BNC, banana jack, and other terminator, connector, adapter and cable hardware. This stuff is not cheap; in fact it is outrageously expensive, but there is no choice. You can't work without it and the people who make it know it."-The Art and Science of Analog Circuit Design, Jim Williams, (ed), Butterworth - Heinemann, 1998, p.275.Resistoid.

author: AcousticBruce
author_rank: Contributor
timestamp: April 16, 2013, 03:01:50 am
content: Well it has to be done... just like the quote says. Btw I am told that I should buy that book immediately. I imagine its around 50 bucks. I definitely do not want a PDF. I like real books.Question:I am looking up BNC connectors and I see the word coaxial and I was wondering is there different types of BNC wiring? What am I looking for I do not want to buy the wrong cables. They look a lot thicker then my oscilloscope probes. How can I look up the proper cables?

author: AcousticBruce
author_rank: Contributor
timestamp: April 16, 2013, 03:09:09 am
content: Hey w2aew what is a BNC 50ohm feedthrough termination for?I noticed on your video you had a 2467 (man that scope is amazing) and it had 1Mohm and 50Mohm options for each channel. My scope only offers 1Mohm.. in fact ever single scope I have owned only did 1Mohm. Is this what these are for? To make that option available?

author: w2aew
author_rank: Super Contributor
timestamp: April 16, 2013, 03:46:56 am
content: Quote from: AcousticBruce on April 16, 2013, 03:09:09 amPrecisely - they're used to terminate the cable in 50 ohms when needed, and your scope doesn't have the option.oh, and yes, the 2467 is an awesome analog scope. I remember buying two of them in the mid/late 80's at the company I was working for, and they were about $13,000 back then!

author: AcousticBruce
author_rank: Contributor
timestamp: April 16, 2013, 03:53:41 am
content: So basically you hook this termination up at the base of the scope, lets say on channel one. Then you hook a scope probe into that?So if I have a 10X probe at 10Mohms and also the 50mohm terminator would this be 60Mohms at 60X? So it would attenuate the signal 60 times? Sheesh.

author: w2aew
author_rank: Super Contributor
timestamp: April 16, 2013, 12:17:57 pm
content: Quote from: AcousticBruce on April 16, 2013, 03:53:41 amYes and no.Yes, you would put the terminator at the scope input. In this case you would NOT be using a 10x probe! You would use the 50 ohm terminator when you are measuring signals that directly drive 50 ohms, such as RF or high speed signal generators. It's function is to properly terminate the 50 ohm coax (transmission line) to prevent signal reflection, standing waves, and distortion.Your typical 10x probes are only used with the 1Mohm input impedance of the scope.There are special low capacitance Z0 divider probes that are used with 50 ohm terminated inputs, but you'll likely not need them. They can be home built to some extent.

author: Resistoid
author_rank: Contributor
timestamp: April 16, 2013, 02:07:09 pm
content: Quote from: AcousticBruce on April 16, 2013, 03:01:50 amYes, AcousticBruce, there are different types of coaxial cables suitable for BNC:1) The cables are available in different impedances, for example 50 ohm and 75 ohm. ("RG-58" for 50 ohm and "RG-59" for 75 ohm).2) The BNC connectors also have different impedances, again for example, 50 ohm and 75 ohm.3) If you are using 50 ohm cables, then you would normally use 50 ohm connectors and so on.4) The coaxial cables themselves can be constructed differently by the manufacturer:i) Some have a solid inner conductor. - This is suitable where the cable is not supposed to be moved around after being placed.ii) Some have a stranded, flexible inner conductor. - This is your best bet where connections are being made and disconnected regularly since it's less likely to break and more convenient. I suspect this is what you'll need.5) There's a chart with several cable types here. RG58 and 59 are near the end:http://www.ko4bb.com/Manuals/12%29_Components_Specs/Coax_Cable_Specification_Chart.pdfA few years ago I bought a 100 metre reel of this RG58U for use with 50 ohm connectors:http://www.soundlightuk.com/shop/products/Black-RG58U-50-Ohm-Cable.-100m-Reel.htmlAnd it's still going strong.I'm in the UK and I got the Jim Williams book on Amazon over here. It's still available in the US:http://www.amazon.com/Science-Analog-Circuit-Design-Engineers/dp/0750670622/Resistoid.

author: AcousticBruce
author_rank: Contributor
timestamp: April 23, 2013, 08:44:50 am
content: Thanks resistoid. I am considering all of this.Question:What is the difference between these two options?1) Hook BNC cable to scope, hook 50 ohm feed through, hook up test leads.2)Hook BNC T adapter, Hook 50 ohm termination to one end, hook BNC cable and test leads to other.

author: Unknown
author_rank: Unknown
timestamp: April 23, 2013, 09:57:03 am
content: The size of the unterminated stub. Ideally you want the terminator right at the scope front-end inside the scope, so the closer the better.

author: AcousticBruce
author_rank: Contributor
timestamp: April 23, 2013, 10:01:27 am
content: Quote from: alm on April 23, 2013, 09:57:03 amMaybe I should ask. Do they accomplish the same thing?Sent from my SAMSUNG-SGH-I317 using Tapatalk 2

author: Unknown
author_rank: Unknown
timestamp: April 23, 2013, 05:48:23 pm
content: Yes at low frequencies, no at higher frequencies. The tee + normal terminator would probably be okay for signals with a bandwidth less than 10 MHz, and I would expect problems for signals with a bandwidth exceeding 100 MHz. Not sure where exactly the limit is. Note that I'm talking about the bandwidth of the signal. A 10 MHz sine will have a 10 MHz BW, but a 10 MHz square wave could easily have hundreds of MHz bandwidth, depending on the rise time.