
7405 
HEX
INVERTER
with OPENCOLLECTOR outputs

POSITIVE
LOGIC



The 7405 IC package
contains six independent
positive logic NOT GATES (INVERTERS). Pins 14 and 7 provide power for
all four
logic gates. The OpenCollector outputs require pullup resistors for
proper logical operation.


[NOT SIMULATION] [NOTTRUTHTABLE]



Since the outputs of the 7405's gates are
opencollector, they can be directly tied together to logically form
different logic blocks without the need of seperate gates. The picture
to the left illustrates the coupling of 3 NOT gates. The LED will light
if any of the 3 inputs (A,B,or C) are LOW and only go out if all input
(A,b,and C) are HIGH. In this way the circuit is behaving like a 3
input NAND gate.
NOT GATE LogicRules:
The output is the inverse of the input, in otherwords if the input is
HIGH then the out put is LOW and if the input is LOW the output is HIGH.

