Suggestions on common capacitors to have on hand

1000uF 16v, 1000uF 25v, 2200uF 16v, 2200uF 25v, 4700uF 25v, 100uF 25v, 47uF 25v, 22uF 25v, 10uF 50v, 1uF 50v all 105deg types.

0u1 200v, 0u22 200v, 0u47 200v 10nF, 22nF, 47nF, 68nF 100v or 200v.

Everybody will have their own ideas on this, and you're right - it does depend to some extent on just what you're repairing. For instance, if you get well into switch mode PSUs, you might want to keep some very good quality low ESR types, and also some front end smoothers which are usually in the region of 47 to 220uF at 400v working. If you get into RF work, you will be wanting some histab small values down in the pF's. The ones that I've listed above, are the sorts of values that I use regularly in general hifi, DVD, CD etc repairs. The TV / CRT monitor boys out there will keep more high voltage types. Over time, you'll get your own collection and preferences, but something along the lines of the above, should see you ok for most low voltage work.

Arfa

Thanks, that gives me a shopping list for the parts store tomorrow. :)

- Mike

While Arfa's suggested list is a good one, I (and probably others) have discovered that Murphy's Law comes into force with a vengeance where components are concerned.

i.e. The capacitor you need for a particular job is nowhwere to be found in your stock of perhaps several hundred or more.

Not only are capacitance value and voltage important but so to is the physical size and shape. Often, where value/voltage and/or space is not critical, you may be able to make do with something other than the original size which you do have in stock, but over time this is less likely to be the case.

I have literally 1000's of electro's in stock which have been ordered in over many years and while they will all measure as new with regard to ESR, they are physically too large for modern electronics equipment. Such is the problem where technology advances result in smaller and smaller components which make the older and larger items obsolete for many purposes.

Take it from me,,, until you have established the major trend of your repair trade, buy in only small quantities (eg,5 - 10 off) of the sizes you are currently using for repairs. Even after you have established your regular stocking list you will often have to buy in a special or a one off (usually fairly expensive) for a particular job. Because you had to do quite a bit of research to find that particular item you might be tempted to buy 10 or so thinking you might have to do a similar job some time in the future. You will probably find them still in the drawer in 5 years time. For smaller types costing less than 20 - 40 cents it won't be a big loss but for anything over $1 you can end up carrying quite an overhead in non profitable stock.

Note what Ross says Michael. It's all good advice that I totally agree with. My shop's component drawers are also full of all those slightly too large electros ... You might have wondered why I specified a couple of different working voltages for similar values in my list. Ross gives you the answer - it's all about physical size.

Arfa

"Arfa Daily" hath wroth:

Same here. I have all the right values, but not in the right form factor or size. To solve this problem, I "stock" a large pile of dead power supplies, motherboards, and cards. If I need a part, I dig out the Pace desoldering contraption and pull a few. It's also a great excuse not to clean up the mess in the shop and to justify keeping old junk around. When I pull an electrolytic cazapitor, I always test it with the capitance meter for value, and the ESR meter, for quality.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Again, this is good advice. A few months back, I got offered a bagfull of two different types of brand new ( smallish ) switchers. They are an endlessly useful source of electrolytics and Schottky diodes. I also keep a box full of replaced DVD decks. It's amazing how often gears and such from these, come in useful. The Panasonic audio CD " traverse deck " for instance, has a number of plastic pins moulded into it. These are a perfect size to replace the cassette door latch pins that break off on Aiwa units, when the belts slip, the mech locks up, and the owners animalise the door open. You'll have to be patient on this Michael. It takes years to build up a useful parts inventory, and to gain the necessary trade savvy to know what's worth keeping, and what needs junking, not that I think I know any engineer who's got that last part quite right ... !!

Arfa

"carneyke" hath wroth:

I use the same method as archeologists. Chronological layering. "The last time I saw this part was about 6 months ago, so it should be about 6 inches from the top of the debris pile". I use the same method for filing documents. I fill up a cardboard storage box and insert dividers with the date visible. I don't have to remember where I put something, just when I buried it.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Ha...I hear you. I returned to my dorm room from the shower one day at university to find that my girlfriend had arrived and "cleaned up" the foot+ deep pile of stuff on my desk. I had to be polite, but it took me weeks to "reorganize" my stuff the way I needed it to be. :-)

Tom

Didn't Sherlock Holmes once complain to Mrs. Hudson that she had removed an essential element of his filing system -- the dust?

Without it, you can't see the chronological order. Of course, being Holmes, he could reconstruct it, but he'd rather be doing something else.