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58 lines
1.2 KiB
58 lines
1.2 KiB
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Exercise 3.73: We can model electrical circuits
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using streams to represent the values of currents or voltages at a sequence of
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times. For instance, suppose we have an
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RC circuit consisting of a
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resistor of resistance
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R
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and a capacitor of capacitance
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C
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in series.
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The voltage response
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v
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of the circuit to an injected current
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i
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is
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determined by the formula in Figure 3.33, whose structure is shown by the
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accompanying signal-flow diagram.
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SVG
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Figure 3.33: An RC circuit and the associated signal-flow diagram.
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Write a procedure RC that models this circuit. RC should take as
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inputs the values of
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R
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,
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C
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, and
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d
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t
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and should return a procedure
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that takes as inputs a stream representing the current
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i
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and an initial
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value for the capacitor voltage
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v
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0
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and produces as output the stream of
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voltages
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v
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. For example, you should be able to use RC to model an
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RC circuit with
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R
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= 5 ohms,
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C
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= 1 farad, and a 0.5-second time step by
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evaluating (define RC1 (RC 5 1 0.5)). This defines RC1 as a
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procedure that takes a stream representing the time sequence of currents and an
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initial capacitor voltage and produces the output stream of voltages.
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