Regolo calcolatore |
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01/01/2001 |
Il regolo calcolatore rappresenta un degnissimo rappresentante di calcolatore analogico (il
soroban invece è un rappresentante dei
calcolatori digitali, fratello o cugino che dir si voglia dei computer
che utilizziamo tutti i giorni). Per illustrare il funzionamento del
regolo calcolatore vediamo come si può fare la
somma utilizzando i due righelli graduati seguenti: This instrument represents a worthy example of analogical calculator (the
soroban instead is an example of digital calculator, a brother or cousin of the modern personal computer we use everyday). To show how the slide rule works, let’s start to see how we can execute an
addition using two identical graduated rules A and B, as you see in the drawing: |
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If you want to add 2 and 3, align first the 0 of the rule B with the 2 of the rule A (see drawing) |
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Doing so we have set 2+. You can read the sum on the mark of slide A corresponding to the second addendum (3). |
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If you want add 2+6 you don’t need to move again the rule (set on 2+), but only to read the sum directly on the figure 6 of the B rule (8 of course). |
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Nelle foto puoi vedere la realizzazione di un
regolo In this picture you see a rule for additions with 20 as end of the scale. |
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Depending on which minimum division you used in the construction of the rule, you will obtain results with higher or smaller accuracy. For two figures additions, you need to increase the marks of the scale as hereunder. |
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With two slides as those you can calculate up to a total of 100.
If we only do addictions and subtractions, the soroban is better of the rule both for accuracy than magnitude of the numbers that you can calculate. |
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Se allineiamo l'1 della scala B in corrispondenza del 2 della scala A otteniamo: If we align the number 1 of B slide with the 2 of slide A, we will have: |
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Now I show you a table of comparison between the scales A and B |
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Here is it the proof that you are doing multiplication! (2x with the previous position)
As other example let’s do 3x2. We align the 1 of B slide with the 3 of the scale A, and we will read the total where the 2 is, on the slide B. |
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To divide, reverse the sequence of the processes. The following drawing show 8:4. Align the 4 on slide B with the 8 on slide A and you will read the total on the slide A, corresponding with the 1 on the B slide. |
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Maybe you noted that the previous drawing is valid
also for 10:5 , 6:3 , 4:2. |
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the total is located out of the scale. To solve this problem, you need to use the index of 10 of the rule B, instead of the 1 (see below) |
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So we obtain the total 1.2. But
... wait a minute, the total is 12, not 1.2. The sliding rule gives only the numbers: this is another disadvantage of the rules. How to locate the dot or how to add ten or hundreds you will get along by yourself. |
Esiste poi una soluzione circolare, con funzionamento del tutto analogo a quello appena illustrato, che presenta i seguenti vantaggi rispetto a quello lineare: All this examples are linear rules: but, using the same principle, there are also circular rules, that give some advantages: No more need to move the rule sometime on the right, sometime on the left; The construction is simplified, indeed the two elements rotate around the same axis; |
Se vuoi sapere come è fatta la scala che permette di fare le moltiplicazioni (e divisioni) e come fa a funzionare allora vai qui. |
If you want know more about how the scales are made and how the rule work, click here. |
01/01/2001 |