hunting for project topic

Thread Starter

prashant kumar dwivedi

Joined Feb 18, 2009
5
i want to make a project on electronics but i am not getting a topic help me out to find a topic.
topic should be such that the project can be used in daily life or can help in advancement.
thank you
prashant
 

KL7AJ

Joined Nov 4, 2008
2,229
Building a super stable crystal oscillator is a good challenge. I'm working on one of those myself, right now. :)

eroic
 

anurag602

Joined Jan 17, 2009
9
@KL7AJ,

u mentioned u plan to make a crystal oscillator. even im working upon making a 10MHz crystal oscillator...do u hav a circuit diagram for it?
atpresent im trying to make it frm a circuit i dwnloaded frm net, but can u explain me wat are pros n cons of connecting the crystal in series and parallel.
 

KL7AJ

Joined Nov 4, 2008
2,229
@KL7AJ,

u mentioned u plan to make a crystal oscillator. even im working upon making a 10MHz crystal oscillator...do u hav a circuit diagram for it?
atpresent im trying to make it frm a circuit i dwnloaded frm net, but can u explain me wat are pros n cons of connecting the crystal in series and parallel.

Greetings!

It is generally better to operate the crystal in the series resonant mode, as the Q is higher. However, the circulating current through the crystal will ALSO be higher in the series mode, so you must carefully choose driving levels. The Butler oscillator is a good choice because both the driving and load impedance of the crystal are very low with this circuit. However, there are still some precautions. You want to use JUST enough gain to sustain oscillation, this assures low enough current through the crystal so it doesn't heat up too much. Don't try to get significant power from the oscillator. The output of the oscillator should be coupled to an infinite impedance buffer amplifier, such as a mosfet source follower.

Hope this helps. There are also some other considerations that may or may not be important to you. One of these is PHASE NOISE, which can actually be degraded by either TOO MUCH or TOO LITTLE feedback. It's very difficult to measure without a spectrum analyzer though.

Eric
 

HarveyH42

Joined Jul 22, 2007
426
I've had a gem of an idea, since getting a new puppy, little over a year ago. My city has complete Wifi coverage, free internet to everyone. Last year, I also got my first GPS. Its small and lightweight, so figured without the screen, it could be much smaller and lighter. The idea is to mate a GPS reciever, with a Wifi modem, to be attached to your pet, child, or most anything that could wonder off, or stolen. It could send its current position either on request or constantly. I know this is way beyond my ablities, but the city-wide hotspot trend is growing fast, something like this could become profitable for somebody in a few years, probably it the time it would take to develop. Quite a few cities already have hotspots, and I understand some wireless networks (home and office) can be used to gain internet access, without the owners knowledge, but not sure about that.
 
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