Discrete Devices
Discrete semiconductors (transistors, diodes, etc.) and optoelectonic devices available in Room 312
Integrated circuits (IC's) are listed separately
Please read the notes following this list.
Notes:
For the purpose of this compilation there is a space between the part prefix
(the letters) and the part number. You should remember that part numbers,
generally, have no intervening spaces.
The part prefix generally (there are exceptions of course!) denotes the
manufacturer of the part. Common ones are: 1N, 2N, 3N, 4N - JEDEC part numbers. JEDEC is not
a manufacturer but a standards association. A manufacturer producing a part bearing a JEDEC number
guarantees that it meets all of JEDEC's specifications and is therefore completely interchangeable
with other manufacturers parts bearing the same part number.
Although I have tried to include some specifications for each part these should only be used
as a guide to selecting a part as being a possible candidate for your application.
A complete data sheet should be consulted to determine if the part will perform satisfactorily.
For instance, the hFE of the 2N3055 is given as 50 but this is true for only one optimal
operating point. In your application you will probably have a significantly lower hFE.
Here is a brief guide to the specs given:
The specifications given are often maximum ratings. To get a reasonable
lifetime from the part you would normally operate it at less than the maximum
rating. For instance, for the LED in the H21A3 you should probably use at most
about 20 mA instead of the rated 60mA.
Some specifications are achievable only in a perfect world. For instance,
the maximum dissipation specification of the 2N3055 is 115W. This is only
achievable if the case of the device is no warmer than 25 deg C This implies the
use of an incredibly large heat sink if the room air temperature is 20 deg C. If
your design must be able to work in a room warmer than 25 deg C (almost always
true then you must derate from 115W.
There are more devices available than what is on this list. I have not
included some parts that are obsolete (or almost there) nor any that were
purchased for repairing equipment.
Part of normal engineering practice is to keep costs as low as possible. To
this end I have indicated those parts that come in metal packages. Metal parts
can be 2 - 5 times more expensive than a comparable plastic packaged part.
Chris Dumont Feb 1 1996