Theory Of Operation; Introduction; Logic Elements; Logic Comparison Diagrams - HP 5340A Operating And Service Manual

4-2. This section describes the individual logic elements, overall counter operation, and theory of
operation for each printed circuit assembly. The overall counter theory starts in Paragraph 4-103.
The theory for each pc board starts in Paragraph 4-137.

LOGIC ELEMENTS

4-3.
4-4. Two states exist in the binary system, 1 and 0. HIGH (H) and LOW (L) are used to represent
the levels of 1 and 0. HIGH always represents the more positive level, whether it be positive or
negative logic. Figure 4-1 shows four pairs of logic symbols that have the same truth tables and
can be used interchangeably. The same function is performed by what appears to be two dif-
ferent logic symbols.
4-5. GATES. Figure 4-2(A) represents a basic
inputs are HIGH. An AND gate may have two or more inputs. Figure 4-2(B) represents a basic
OR gate. The OR gate output is HIGH if one or more of its inputs is HIGH. An OR gate may
have two or more inputs.
,
!I
SECTION IV

THEORY OF OPERATION

A
I
AND
gate. The AND gate output is HIGH if all
Model 5340A
Theory of Operation
C D
A
L
L
L H
L
H
Z
L
4-1