Manual

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T
his next circuit is a logic OR circuit. Are you able to
guess how this circuit may work? Remember that
the AND circuit produces high logic only when
i
nputs A and B are both high. In the OR circuit logic
high is produced when A or B receives a logic high
input.
By connecting either terminal A or B to terminal 119
(logic high terminal) the display will show H. Try
connecting each of the terminals to terminal 119;
then to terminal 124. What occurs? When
connected to H the output is high when either A or B
is connected. A+B is the symbol for this logic
function.
We won’t explain the entire operation for you here
because this circuit is similar to project #29.
Compare these two projects (29 and 32); then make
n
otes of their similarities and their differences. On
the schematics diagram see if you can follow the
circuit.
Notes:
EXPERIMENT #30: “OR” DTL CIRCUIT WITH DISPLAY
Schematic
Wiring Sequence:
o 71-41
o 72-19-18-21-22-23
o 79-25-48-124
o 81-47
o 83-127-125
o 84-80-46
o 85-42-119
o 86-82-40
o 121-122
o 126-(to 119 “HIGH” or 124 “LOW”)
o 128-(to 119 “HIGH” or 124 “LOW”)
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