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        <div id="content-top1">Page 21 - Linear Control System D'Azzo (5th Edition)</div>
        <div id="content-top2">P. 21</div>
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    <pre style="white-space:pre-line"><code>Introduction  3

                           FIGURE 1.2 Open-loop control systems: (a) automatic toaster; (b) electric motor;
                           (c) functional block diagram.

                               Systems in which the output quantity has no effect upon the input
                        quantity are called open-loop control systems.The examples just cited are repre-
                        sented symbolically by a functional block diagram, as shown in Fig. 1.2c. In
                        this figure, (1) the desired darkness of the toast or the desired speed of the
                        motor is the command input, (2) the selection of the value of time on the

Copyright Â© 2003 Marcel Dekker, Inc.</code></pre>
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