[TriEmbed] Giving this Surface Mount Thing a Try - Transistor Help Needed

[Glen Smith]

As the saying goes "The nice thing about standards is there are so many to
choose from."

I am most familiar with PCB's having R1, R2, R3 ... for Resistors, C1, C2,
C3 for Capacitors, D for Diodes, L = inductors, J = Jumpers or connectors,
Q = Transistors, U = IC's & X = Crystals. In smaller designs, it probably
does not matter too much. There is certainly something to be said for
RC(ollector), RE(mitter), and RB(ase). Many transistor circuits have a
biasing resistor from Vcc to Base and Base to Gnd, so now you have a RB1 &
RB2 or something. If your PCB has more than one transistor circuit, the
naming convention can get kind of hairy.

Truth be told, you can call them Charles, Chip, Glen, Pete and Jon if you
want to and you document it well. (Which is true regardless.) I just wanted
to be sure that I could use what I am familiar with when I started using a
PCB layout package.

Glen


On Fri, Mar 21, 2014 at 3:47 PM, Charles McClelland <chip at mcclellands.org>wrote:

> Glen,
>
> I am using EAGLE - it allows you to set the names so I guess I have to
> take responsibility  - Resister Base (RB)  - I am learning so if there is a
> better naming convention I should be using, I would be open to it.
>
> Thanks,
>
> Chip
>
>
> On Mar 21, 2014, at 1:29 PM, Glen Smith <mrglenasmith at gmail.com> wrote:
>
> Charles,
>
> As Bill said, there are single gate IC's to do what you want, a quick
> glance indicates the cheapest (in one'sie two'sie quantities) is $0.33. But
> there are 2222 transistors available in SOT-23 packages: Jameco has them
> here:
>
> http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&freeText=2222%20sot-23&search_type=jamecoall
> qty 10 available at $0.09 each. Or, to keep the comparison, DigiKey has
> them here:
>
> http://www.digikey.com/product-search/en?pv7=2&FV=142c0042&k=MMBT2222A&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25
> (for one'sie two'sie quantities) at $0.18 each.
>
> It has been far too long since I did transistor circuit design to tell you
> whether what you have will do the inversion you want, but you can hook it
> up on a breadboard with your discrete's and see how it works.
>
> Since I'm sending this note anyway, is there a reason why you chose RA, RB
> RC designations? It took me a few minutes looking at your circuit to figure
> out that it was a designator rather than a ResistorCapacitor (RC) network.
> Maybe it is just what I'm used to working with. Which layout tool are you
> using? KiCAD or Eagle? If one of them forces me to use RA, RB, RC - I think
> I will use the other.
>
> Glen
>
>
> On Fri, Mar 21, 2014 at 12:46 PM, Bill Farrow <bill at arrowsreach.com>wrote:
>
>> Charles,
>> There are single logic gate ICs in surface mount which should do what you
>> want. Here's my quick digikey search.
>>
>>
>> http://www.digikey.com/product-search/en?pv247=24&pv64=1&pv667=1&pv69=3&FV=fff40027%2Cfff8019d&k=single+gate&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25
>>
>>
>> Bill
>>
>>
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>>
>
>
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