Newsgroups: comp.robotics
Path: brunix!sgiblab!swrinde!cs.utexas.edu!howland.reston.ans.net!spool.mu.edu!torn!news.unb.ca!csd.unb.ca!michael
From: michael@jupiter.sun.csd.unb.ca (Michael Thompson EE)
Subject: Re: PWM speed controllers
Message-ID: <1994Mar25.202304.26726@jupiter.sun.csd.unb.ca>
Organization: University of New Brunswick, Fredericton, NB, Canada
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References: <1994Mar25.181542.14843@mcshub.dcss.mcmaster.ca>
Date: Fri, 25 Mar 1994 20:23:04 GMT
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Tom Bering (beringt@ncc1701.eng.McMaster.CA) wrote:
: Not Yet.  You need to switch the sign of the feedback loop, and
: to redirect the signals going into the H-Bridge.  I researched
: all of the servo control chips I could find a while ago.  The
: important variable for all of them was the power level you were
: operating at.  If you were in the required voltage/current range,
: many of the chips would work.  If you were outside that range, you
: needed a chip like the LM638/639 which is a general purpose design.
: The important variable is what are you trying to do ?

I'm trying to design a speed control for R/C ships, etc. The pictures of
the units in Scale Ship Modeler, the Subcommittee Report, etc. are all
small (in size) and seem to be based on one chip. I found a Precision Servo
made by Ferranti (ZN409) in a magazine but I'm looking for something a 
little easier to get a hold of and most likely cheaper.

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Michael G. Thompson                         
Electrical Engineering Dept.
University of New Brunswick
Fredericton, New Brunswick
Canada  E3B 5A3

mgt@unb.ca
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