donjonson Post subject: Building a 16Mhz radio for Senior design
project. have Q's Posted: Wed Sep 19, 2007 7:23 pm Lieutenant
Joined: Wed Sep 19, 2007 6:58 pm Posts: 3 Hello Very
Happy This is my first post on this forum. I am building a 16Mhz radio
for my senior design project and Have a few questions. I have been working
in PSPICE and am ready to start building and testing. 1)What
kind of capacitors should I use in my tuned amplifiers, oscillators,
and filters? I have been looking online and there are so many to choose
from. I think I should be using something with a small temp coefficient
but what material should I use etc.. 2)Does anyone know of a
place online with low shipping costs and a good selection of components?
I have been looking at mouser it seems to be pretty good any other suggestions?
3)In my transmit oscillator I am using an NFET to switch in
and out a cap. I am having a difficult time trying to Find one in a
TO-92 package with a good enough Ft. Does anyone know where I could
go to get this? or perhaps suggest a better device for me to use than
an NFET. thank you for taking the time to read and answer my
questions. I posted this in the amateur radio forum first but
I noticed it is pretty much a dead forum so I reposted it here. If a
moderator wants to delete one of them please delete the other one.
Top IR Post subject: Posted: Sat Sep 22, 2007 2:51
am Site Admin Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373 Location: Germany Hello donjonson, First of
all, welcome to our forum! To answer some of your questions:
Quote: 1)What kind of capacitors should I use in my tuned
amplifiers, oscillators, and filters? I have been looking online and
there are so many to choose from. I think I should be using something
with a small temp coefficient but what material should I use etc..
In principle, you should use high Q capacitors. As for the material
you are right there are materials with large temperature coefficient
like Y5V. You should use X7R or X5R capacitros which have a low temperature
coefficient. Quote: 2)Does anyone know of a place online
with low shipping costs and a good selection of components? I have been
looking at mouser it seems to be pretty good any other suggestions?
You can try: Digikey www.digikey.com Quote: 3)In my
transmit oscillator I am using an NFET to switch in and out a cap. I
am having a difficult time trying to Find one in a TO-92 package with
a good enough Ft. Does anyone know where I could go to get this? or
perhaps suggest a better device for me to use than an NFET.
While NFET is a good choice I would not limit myself to a specific
type of package to allow more flexibility. Thre are many types of packages
available besides TO-92. Here are number of TO-92 NFET transistors
from Vishay-Siliconix: https://www.vishay.com/docs/70237/70237.pdf
Quote: I posted this in the amateur radio forum first but I noticed
it is pretty much a dead forum so I reposted it here. If a moderator
wants to delete one of them please delete the other one.
posts with topics which are relevant to the Forum are not deleted.
I am moderating this forum for almost 2 years now and have met
here people with reach knowledge from whom you can only learn.
Good luck -IR
Posted 11/12/2012
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