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From: v129raaq@ubvmsd.cc.buffalo.edu (Richard T Ciesla)
Newsgroups: sci.electronics
Subject: motor speed controller, transistor question
Keywords: using this for R/C car
Message-ID: <68137@eerie.acsu.Buffalo.EDU>
Date: 1 Apr 91 17:39:33 GMT
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	Hi everybody. I am trying to build an electronic speed controller
for a radio controlled car's motor. The radio receiver that I have has output
plugs with three wires that normally go to a servo. I would like to use the
output pulses converted from the radio signal to control a 555 timer, which
would in turn switch on and off transistors to control the motor. I want the
timer IC to send out a variable high frequency determined by the output from
the radio control system. This high frequency would switch the transistors on
and off so fast that the motor will keep turning, with faster switching making
the motor go faster. I would like to have the transistors bypassed when the
motor travels at full speed.
	Also, I am using transistors rated at 15 amps each. If I wire them up
in parallel, will the amp rating increase (ie 3 transistors@15 amps = 45 amps?)
	And if anyone out there is really familiar with R/C car electronics,
I would like to hear from you, because I have other questions of a more detailed
nature.
	Any replies would be appreciated. Thanks.

Rich Ciesla
v129raaq@ubvmsd.cc.buffalo.edu