Having some trouble finding components.

[tonequester]

tonequester here.

I have been trying to find a source for a 50W. X 30 Ohm power resistor. Does anybody know of a good source. I felt sure that either Digi-Key, or Mouser would be a sure thing, but they have a funky search engine you must use. All "fields" apparently have to be filled in for it to get results. You have to provide manufacturer,
temperature co-efficient, etc., and I played with it for quite sometime with no luck. I Googled the item, and didn't fair much better. The closest I came was a 100W. with adjustable tap, which would work but it's over-kill for my purpose. I guess I'm going to have to buy the Mouser paper catalogue. I even tried Radio Shack, but no results there either. Any ideas would be appreciated. Thanks for any replies. tonequester.

[JoeM]

WH50-30RJI Welwyn Components | Mouser

[J M Fahey]

Or one of these:
Wirewound Resistors - Chassis Mount | Mouser

[tonequester]

tonequester here.


Greetings JoeM, and thanks so much. What service ! You evidently have that Mouser search engine down pat. I just knew that they would carry the needed resistor,
but my search abilities are greatly lacking. I'm not only new here, but new to computing in general. My kids say I need to refine my searches. I guess I'm just not refined enough.
I really appreciate your guidance here. I'm spending more time looking up parts than building projects. Thanks again, and have a great day ! tonequester.

[tonequester]

tonequester rere.


Thanks once again JM. I'll certainly check your lead out. Looks like there is a better way to find what one wants at Mouser than the method I tried. I used to get their catalogue by mail for free. I believe I'll go ahead and pay for one. It will be worth the time spent Googling, as Goggling is obviously NOT my forte. Thanks much for the help !
tonequester.

[bkahuna]

Most of the time, Mouser's online search will get you what you want, but sometimes there's just no substitute for a paper catalog.

I was searching for a plastic enclosure the other day, online, for a project I'm building, and wasn't able to find something suitable, so I picked up the catalog and found what I wanted in less than 2 minutes. The biggest problem, online, is that different manufacturers have different ideas of what the specs should be called. For example, one manufacturer uses Length, Width and Height, while another uses Height, Width and Depth. Some use only metric units, some use only English, and there are separate columns for all of these in the search feature. It can get very frustrating. Then there are the times you search, and find the perfect part in 10 seconds!

I say start online, and back it up with a catalog, if necessary.

[tonequester]

Tonequester here.


Greetings bkahuna ! It's good to "make your aquaintance" on the forum. I'm glad(not at your expense) that somebody else, at times has trouble with those specialized
"search engines" besides me. I know that in the old days, with the hugh Mouser catalogue I was always able to find what I needed in just a couple of minutes, plus I just liked browsing it.
I got many a good idea from the old caalogue. now I've come to dread the on-line version. It seems that I am typically looking for some odd-ball item that none of the smaller electronics
dealers stock. I'm going to order the catalogue. Another person replied to a similar post that I made a while back, and he claims that if you make "regular" orders, Mouser continues to send you catalogues for free. Thanks for the opportunity to "meet" you, and for your take on this issue. This is what being "old school" gets one now-a-days. I have to admit I long for the days of free catalogues. I used to send off for them constantly : Mouser, Digi-Key, Edmund Scientific, Even the old Johnson catalogue with the "x-ray glasses" and such. Kids today don't realize what they are missing. I never in my youth would have had 3-4 hours in any given day to play video games. If I wasn't trying to build something, I was tearing something up to figure it out. You have a great day my friend ! tonequester.

[JoeM]

Hi tonequester,

Well, I do have some experience with Mouser, back when their paper catalogs were only about a 1/2 inch thick. The online search gives so many options that it can be somewhat intimidating, and they carry such huge parts inventory.

[tonequester]

tonequester here.


Greetings JoeM. I have what I think is good news concerning the Mouser paper catalogue. It appears that they are again offering it free of charge. I just registered with them
in order to get one(they even give you the choice of "one time only" and continuing subscription) You just go to their website and click on "catalogue" at the top, it gives you the option for a printed catalogue. If you"re like me, it's a good "read" even if you don't order all that much from them. Thanks for your help, tonequester.

[Chuck H]

When I first started ordering with Mouser thier catalog was about as thick as a magazine. Now it's the size of a metro area phonebook! The sent me a new catalog every three mo's for a couple of years before I put the kabosh on it. For all the catalogs they sent I could have bricked a walkway or possibly made a tidy living recycling paper! Anyhoo... You don't really need a new catalog as often as they send them. I order maybe US $200 a year from them. Four three and a half inch thick brochures seems excessive. And I just couldn't ignore it in good concience.

I do use the paper catalog. But now I order a new one when the old one I have seems sadly out of date. Otherwise I use the online search engine. It does take some getting use to. But it's a small price for the life of half a dozen trees! The online search engine is (obviously) harder to negotiate than the paper catalog. But, even at it's extreme size, the paper catalog doesn't list all of their 'in stock' inventory. It's definitely worth getting to know the search engine at Mouser.

The aluminum housed (built into an aluminum heat sink) resistors are a really good value. They are "wire wound". If you go to any search engine and plug in "mouser" the link will offer a "passive components" option for site access. Then select "resistors". Then select "wirewound resistors". Then choose "50 watts" and "stocked" on the filters. A few different options for the chassis mount type, aluminum housed resistors will be in the first ten selections.

Just take a little time and get to know Mouser's search and filter engine. And get "a" paper catalog. You can find almost anything, component wise, at Mouser. Oh... And they have a new flat shipping rate. It was something like $10.50. But it just reduced to seven dollars and change. Nice. I always find myself placing a small order with them at the end of a project. Saving three bucks may seem like small taters. But when the order is less than the shipping it gets right under my skin. So their effors to curb this are appreciated.

[tonequester]

gottonequester here.

G'day Chuck ! Thanks for the advice on the Mouser search engine. I do not intend to give up on it. It's the wave of the present, and future. I did order the paper catalogue
when I found out that they weren't $8.00, as I had been told. you've got a good point on the trees as well. It's not that I don't think that the paper catalogue is worth the money, I do.
I just haven't done much in the last couple of years. I had been itching to do a project before joining the forum. Now, the itch is terminal. I had forgotten how much I enjoy the whole thing.
I've never had the opportunity to even "talk" electronics but rarely. Now, the info and opinions are bombarding me so fast that I have to print what seems to be the really applicable stuff.
It allows me to get comfortable and try to thoroughly understand what I can, and take notes so I can question that which Google or my books fail to explain adequately. Once again, thanks for your timely reply. The advice is always welcome. Sincerely, tonequester. Quote : "If thou wilt incline thy ear, thou shalt receive instruction : and if thou love to hear, thou shalt be wise". Ecclesiasticus 6 : 34 (I'm a Hopeing.)

[Enzo]

TQ, the search parameters don't have to be all selected, they are just there to help filter the results. You can select just 50 watts, and instead of thousands of entries you might now see only hundreds. Click apply filters than you can research with some other thing, like the resistance or mounting style. You need not use all of them.

The online search is great for finding something you know, like a 50 watt 30 ohm resistor in aluminum. But the paper calatlog is best for learnig the sorts of things they even have. Many times I spot something I never knew was even manufactured. And the other advantage of the paper thing is the pictures. If I need a 24v SPDT relay, I can find many, but if I am replacing one on a circuit board, I need to shuffle through the pages to find one that looks the same, at least enough to make it fit the same hole pattern.

Here is a sample search at Mouser. NUmber in parens is the amount of entries that result.

Search "30 ohm 50w" And a list of categories appears. CLick on resistors (375)

ANother list of categories. Click on the physical form you want, Either wirewould or chassis mount. I'll chose chassis mount, those are the ones with mounting holes as opped to just wire leads. Note that probably most of the wirewound 50 watt resistors are also chassis mount, thus the similarity in numbers. So click chassis mount (238)

Woops, another short list. Don;t know what planar ones are so click on wirewound (see we got to wirewound anyway)
And now finally a bunch of sorting parameters. and 232 matches or entries.

At this point I start checking the STOCKED box for each step. No point cluttering the results with things they don;t have. Check the box. Note the 232 matches changes to 118. I always click on the eneable smart filtering box, but you don;t have to.

Now I can select several things or one at a time. I don;t care what brand, so I ignore that. So next item is resistance. Scroll that down to 30 ohms. Click 30 ohms. Now the thing goes from 118 matches to only 10. I click APPLY FILTERS, and that 10 entry list is what is left.

Those 10 are easy enough to look through, but let us continue. From the power column, click 50 watts. (we could have clicked 50 watts at the same time we did 30 ohms) and apply filter. That leaves 7 choices.

At this point you can probably just select one. The remaining parameteres may or may not be useful, so ignore them if not. SO consider what the use will be. I suspect the 5% is fine, but if 1% really matters, then select that. I leave it out becaue 5% is good enough in my view. I can't imagine temperature coefficient matters to you so ignore it, same with "series", and even the temperature range is pointless. -55 degree to 200 degrees is way beyond anything our equipment faces. Dimensions? If you have a space issue and need to fit within an area, then pick one, otherwise ignore dimensions.

SO at this point I'll just stop selecting and look at the 7 entries they show. They range from $2.80 to $17. I'd pick by price, $2.80 or $3.26 for the Welwyn or Arcol. A couple are $9, but looking closely we see those are non-inductively wound. UNless you need that specifically, why pay extra for it? Eliminate those in your mind, and the $17 one too. That leaves a couple or Dale choices at $5.

That took longer to write than to do.

[tonequester]

tonequester here.


Thanks for your time Enzo. You gave me an excellent explanation of that search engine. It never occured to me that I should try just one parameter at a time. once again
me-thinks common sense alluded me. I've printed this off so I can refer to it until the search comes naturally. I have ordered a paper catalogue, and mainly for the reasons that you mentioned. I always found it a "good read' , and several of my past projects began with some time spent looking through the catalogue without a project in mind. I don't know how Mouser stacks up on price these days, but I have found that if you can't find what you need there, you are going to probably be in for quite a search. Sorry foryou having to write so prodigiously, but I am very appreciative that you did. I hope you have a a peaceful, and happy day from here on out. tonequester.

[Enzo]

Mouser prices are competitive. You may find a lower price on a specific item somewhere else, but as a general shopping place it is fine, it is my primary go-to.

I make up a shopping list on a legal pad. I then make columns of prices across each line. I usually list Mouser first. If it is a large order I also check at Digikey and Allied. If I split an order between two suppliers, I keep in mind I will then pay two shipping bills, so any price savings on something have to cover the second shipping or there is no point. Also, not all vendors have all the parts, or one may be out of something I need.


Some things are industry specific, like 500v caps, tube sockets, reverb pans, so I use different suppliers for those.

[tonequester]

tonequester hear.


Hey Enzo ! Thanks for the tips. I haven't yet found everything I needed, but I'm going with Mouser on everything I can. I like your shopping list idea. I think that I'll be able to get everything except the big heat-sink there. It's almost the cost of the kit, but I don't have much choice on that item. I think when all is said and done, I'll have no more than $150.00 in it, and that isn't bad for anything 50-100W. Everone seems to regard Velleman pretty highly . I should have replaced all circuitry on my guitar by next week, so I'll be ready to start ordering then. Thanks again for your advice, on ordering parts, and using the Mouser search engine. Hhave a great day. tonequester.