Ah! I learned a little more. Thanks!
I was looking at the crystal in the schematic for Galaga yesterday
wondering how the heck it worked without any power input. <light bulb
turns on> The inverters are getting +5!
PS So, if I find an oscillator at the proper MHz, can I sub it for the
crystal and all it's feedback components? Not that I want to but if I
*NEED* to at some point. Just cut the trace from the crystal circuit to
it's first flip-flop (or whatever it's driving) and pump in the oscillator
output in it's place. Right?
aek@spies.com (Al Kossow) on 01/19/99 01:28:08 PM
Please respond to vectorlist@mcfeeley.cc.utexas.edu
To: vectorlist@mcfeeley.cc.utexas.edu
cc: (bcc: Franklin Bowen/MD/CheckFree)
Subject: crystals vs crystal oscillators
the bigger difference is a crystal is a passive component and can be
thought of as a inductor/capacitor with a very high 'Q' (roughly, the
'bandpass' of the tuned circuit). an oscillator adds an active feedback
circuit to create an 'oscillator'
most of the time, on video games, the active component is two inverters
hooked in series with a crystal somewhere in the feedback path.
Received on Tue Jan 19 12:52:33 1999
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