Online parts stores? Where do you buy your stuff?

Both will send you huge, detailed catalogs if you ask or place an order, that are often handy to look through to find something before you are sure of the key words for a search.

There's also bgmicro.com/ allectronics.com, and skycraftsurplus.com.

Anyone know if anyone still sells bags of misc. switches, diodes, etc like they used to?

I'm also curious about bags (1000-lot) of general purpose transistors, as well. I used to find them at about $10 each (1 cent/BJT) quite often, but not so much anymore. (I give these away to students, which is why the desire for cheap and general purpose and 1000's.)

Jon

I look for that sort of thing on eBay, these days.

e.g.

But check against the quantity price at Digikley and Mouser before bidding.

I've spent time on ebay regarding this very issue. I rarely find the kind of deals I'm looking for, plus the risk is higher than buying from the surplus places who used to carry these bags as a more regular matter. For example, the 2N3904 link you provided is a minimum of $12 for 300 pieces. That's 4 cents each. A 'buy it now' is $14. Higher still. Plus, I'm at risk on ebay. I've had troubles in buying from unscrupulous folks there with 'high ratings' and I don't relish the idea of risking more of the same. Not at those prices. Anyway, at that rate, you are right that I should consider places like digikey and mouser. Peace of mind and reasonable pricing, sometimes.

The other two are starting at $17/1000, which isn't too bad but still almost twice what I paid a few years back. And that's only assuming I can get them at the starting bid. I'll consider the idea. Wish it were cheaper, though.

By the way... why is it that the TO-18's R(theta_JC) is no better than for those little plastic TO-92's?

Jon

Jonathan Kirwan wrote: (snip)

The metal surface the die is mounted on is not the one that gives off the heat, but is welded to it. The heat goes out in all directions through the epoxy in a TO-92.

By the way, there are some high power sort-of TO-92 transistors made with heavy copper lead frames, where you heat sink through the collector lead (real short and soldered to a large copper area). Zetex makes these. e.g.:

They also have one flat side and one mostly flat side, so they can be better clamped between two flat heat sink surfaces with only a thin layer of epoxy on each side.

Or even if you ask them not to send you the catalogs. I bought $5 worth of parts from Mouser once, and they've spent 10 times that on postage since then :-).

Funny you mention that... I bought a $38 car part from a guy (with high positive feedback) on eBay; it arrived broken. Seller was a jerk; it took a Dispute with PayPal to get my money back. (Took 30 days, but it was finally settled.)

Don't be shy of filing a dispute with PayPal if you have a bad seller.

Michael

Been there, done that. Still, life is just too short for it. I avoid ebay most of the time. (It has to be a very, very serious enticement to get my attention.)

Jon

I had earlier imagined that such must be the case. I also opened them, so I know first hand what it looks like in there and agree with your point for those I've opened. Is this the same case, though, for those in TO-18, where there are only two leads coming out and the case is the collector? Did they do that in those cases __because__ they were doing something more like what I see in TO-3 cans, where heat removal is more important?

And I see what you mean about the heat sinking in that Zetex part. Those things are EXPENSIVE, though. 77 cents in 100's and almost 50 cents in 1000's. And the Rth is still at 150 K/W to ambient (which isn't too different from what I'd expect as the package surface area and plastic material is the same.) I seem to have remembered about that figure for TO-92s, generally. The 50 K/W to case seems just a little lower, so that's nice. Not excessively so, enough to make it worth that much to me.

Thanks, Jon

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I've bought a lot of stuff from eBay and had very few problems. I never bid on anyone who has less that a 98.6 approval rating. If they have a high score (such as in the thousands) and a high approval rating they must not be too bad.

Not at those prices. Anyway, at

Places like All Electronics used to sell a bag of resistors, switches etc for about a dollar. I guess they decided they can make more money by cataloging each individual piece. I have several things that need new switches and I'm not that particular as to what it looks like. In any case I've ordered a lot of stuff from All Electronics and never had any problems.

transistors,

which

I bought a "New In Box" DVD recorder on eBay and it turned out to be "factory refurbished" which means it probably had something wrong with it so it was returned. I did the PayPal dispute thing and it would have ended up costing me several dollars to end up with nothing, so I kept it. It died shortly after the brief warranty expired. PayPal, however, didn't give me any crap.