Page 294 - FUNDAMENTALS OF COMPUTER

294 Fundamentals of Computers NPP

Truth Table for 2-input OR Gate Xmo BZnwQ> dmbo OR JoQ> H$s gË` Vm{bH$m

Input Output
A B Y
0 0 0
0 1 1

1 0 1
1 1 1
The same concept may be extended to more Bgr Ho$ AmYma na Xmo go A{YH$ BZnwQ> dmbo OR
than two inputs. One thing to be remembered JoQ> H$m g§Ho$V d gË` Vm{bH$m ~ZmB© Om gH$Vr h¡Ÿ& Ho$db
is that in case of OR gate the output is 1 when
at least one of the inputs is 1. The symbol and EH$ ~mV H$m Ü`mZ aIZm hmoJm {H$ EH$ ^r BZnwQ> Ho$ 1
Boolean expression for 3-input OR gate can be hmoZo go AmCQ>nwQ> 1 hmo OmEJmŸ& VrZ- BZnwQ>m| dmbo OR
drawn as: NPP JoQ> H$m g§Ho$V d gË` Vm{bH$m Bg àH$ma h¡:

A
B
Y = A + B + C
C

The truth Table for 3-input OR gate is: 3-BZnwQ> OR >JoQ> H$s gË` Vm{cH$m :

A B C Y=A+B+C

0 0 0 0
0 0 1 1
0 1 0 1

0 1 1 1
1 0 0 1
1 0 1 1

1 1 0 1
1 1 1 1

OR Gate using Switches pñdMm| H$s ghm`Vm go OR JoQ> ~ZmZm
Consider the simple electrical circuit EH$ gm_mÝ` {dÚwV n[anW H$mo XoImo {Og_| g_mZmÝVa
containing switches in parallel:
_| pñdM bJo hþE h¢…