A Symbolic Analysis of Relay and Switching Circuits
A Symbolic Analysis of Relay and Switching Circuits
A Symbolic Analysis of Relay and Switching Circuits
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15<br />
therefore necessary to manipulate the expression into<br />
the form in which the least numb~r<br />
<strong>of</strong> letters appear.<br />
The theorems ~iven<br />
above are always sufficient to do<br />
this.<br />
A ].1ttle practice in the manipulation <strong>of</strong> these<br />
s;rm1:o1s is 811 that is required.<br />
Fortunately most <strong>of</strong><br />
the theorems are exactly the same as those <strong>of</strong> numerical<br />
al~eora--the associative, commutative,<br />
<strong>and</strong> distribut1ve<br />
laws <strong>of</strong> algebra hold here.<br />
The writer has found<br />
theorems 3, 6, 9,14, 15, 16a, 17, <strong>and</strong> 18 to be especlally<br />
useful in the simplification <strong>of</strong> complex axpres<br />
sian s.<br />
AS<br />
a n exampl e <strong>of</strong> the 81mp11 fica tion <strong>of</strong> expressions<br />
consider the circuit shoWn in Fi~. 5.<br />
~.-.<br />
5'<br />
v<br />
y<br />
_-.....--0 0---0 •<br />
~ WI<br />
Fi Q;. 5<br />
•<br />
x<br />
o<br />
z'<br />
...... '0<br />
Z<br />
The hind'3rance function X ab<br />
for this circllit<br />
will be:<br />
X ab<br />
= W+\\II(X+Y) + (X+~HS+W'+e)(~'+Y+S'V)<br />
,<br />
~ "i\[<br />
= ~+X+Y+(X+~)(S+l+g)(gl+Y+stV) v<br />
= W+X+y+g(~'+S'V)<br />
lthesa reductions walee made \'V1"tth 17b using first ~N,<br />
then X <strong>and</strong>