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From: rcflyer@vnet.ibm.com
Subject: Re: Servo control...
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Date: Tue, 21 Feb 1995 13:50:43 GMT
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References: <1995Feb21.015352.194775@zeus.aix.calpoly.edu>
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In <1995Feb21.015352.194775@zeus.aix.calpoly.edu>, cmayer@harp.aix.calpoly.edu (Chad Erich Mayer) writes:
>Hi--I've been wanting to build a simple servo control using a 555 or 558
>IC timer so that I can directly control a servo with a potentiometer but
>I wanted to know if anyone has already done this and know exact resistor
>and pot ohmage values and capacitor values so I don't have to experiment
>a million times to find them out. I don't know the exact pulse length or
>time. I wanted to use a 558 because I could then control pulse width and
>time pretty simply. I would rather use a 555 because of its convenience
>and price but I don't know how to configure it so that a specific pulse
>can be generated. (The length and duration of pulse). If anybody can help me
>with any ideas-
>
>-PLEASE write me..
>
>Thanks..
>
>Chad Mayer

Here is an ASCII diagram of the circuit on page 7-65 of the 1989 Signetics
"Linear Data Manual Volume 2 Industrial":




                                                         o  5VDC
                                                         |
             5k pot             4.3k                     |
      x---/\/\/\/\/\/--------/\/\/\/\/\-----------x------x
      |                                   ________|______|_______
      |                                  |        4      8       |
      x----------------------------------|7                      |
      |      1N457 diode                 |                       |          output
      x--------->|---------------x-------|6                     3|------------------
      |                          |       |      NE555            |
      |       68k                |       |                       |
      x---/\/\/\/\/\/\/-----x----x-------|2                      |
                            |            |_______1_______5_______|
                            |                    |       |
                           _|_                   |      _|_
                           ___  0.33uf           |      ___  0.1uf
                            |                    |       |
                            x----------x---------x-------x
                                       |
                                       |
                                     -----
                                      ---  Gnd
                                       -



Jerry Pearce                       rcflyer@vnet.ibm.com

