Maker Pro
Maker Pro

Online parts stores? Where do you buy your stuff?

hi,
I've been looking around for a good online store to chop for things
like Transistors, Diodes, Resistors ... etc
Does anyone know of a good/reliable online store for things like
that?

It has to have a location in the US.

Thanks
RK
 
J

John Popelish

Jan 1, 1970
0
hi,
I've been looking around for a good online store to chop for things
like Transistors, Diodes, Resistors ... etc
Does anyone know of a good/reliable online store for things like
that?

It has to have a location in the US.

http://www.digikey.com/
www.mouser.com

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.
 
U

Ulysses

Jan 1, 1970
0
hi,
I've been looking around for a good online store to chop for things
like Transistors, Diodes, Resistors ... etc
Does anyone know of a good/reliable online store for things like
that?

It has to have a location in the US.

Thanks
RK

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?
 
J

Jonathan Kirwan

Jan 1, 1970
0
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
 
Jonathan said:
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.)
I look for that sort of thing on eBay, these days.

e.g.
http://cgi.ebay.com/DTC143ES-TP-NPN-Transistor-1000pc-Lot_W0QQitemZ150135316453
http://cgi.ebay.com/DTC124ES-TP-NPN-Transistor-1000pc-Lot_W0QQitemZ150135317992
http://cgi.ebay.com/2N3904-General-Purpose-NPN-Transistors-300-Pieces-lot_W0QQitemZ140131874406
http://cgi.ebay.com/Lot-Of-1000-Zener-Diodes-5-6V-5-6-Volts-500mW-DO-35_W0QQitemZ120133300040
http://cgi.ebay.com/1-Lot-of-1000-Rectifier-Diodes-1N4001-New-parts_W0QQitemZ320128828674
http://cgi.ebay.com/HUGE-LOT-ASSORTED-LEDs-LED-LIGHT-EMITTING-DIODE-3mm-5mm_W0QQitemZ200121803262

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

Jonathan Kirwan

Jan 1, 1970
0

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
 
J

John Popelish

Jan 1, 1970
0
Jonathan Kirwan wrote:
(snip)
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?

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.:
http://www.zetex.com/3.0/pdf/ZTX851.pdf
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.
 
T

Tom Horsley

Jan 1, 1970
0
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.

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 :).
 
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.


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
 
J

Jonathan Kirwan

Jan 1, 1970
0
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.

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
 
J

Jonathan Kirwan

Jan 1, 1970
0
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.:
http://www.zetex.com/3.0/pdf/ZTX851.pdf
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.

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
 
U

Ulysses

Jan 1, 1970
0
Jonathan Kirwan said:
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.

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
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.

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.
 
U

Ulysses

Jan 1, 1970
0
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.

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.
 
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