Service manual

STP 11-25R13-SM-TG
Q - 21
c. OR Gate
. The OR gate performs the mathematical operation of disjunction. Any input or all
inputs present will produce an output. Figure Q-8 shows the symbol, truth table, Boolean expression, and
waveforms.
Figure Q-8. OR Gate
d. NOT Function
. The NOT function is performed by an inverter that performs the mathematical
operation of negation. An inverter is an amplifier with an inverted output. Figure Q-9 shows the inverter.
Figure Q-9. The NOT Function
(1) When the NOT function is used in conjunction with another gate, it is usually drawn in a circle.
Figure Q-10 shows an AND gate with inverted inputs.
Figure Q-10. Using Circle to Denote NOT
(2) Now that the three basic gating functions have been covered, prepare to derive some other
fundamental gates.