Video Transcript
The diagram shows three NOT gates
connected as a part of a logic circuit. If the input is one, what is the
output?
Okay, so first of all in the
diagram, we can see one NOT gate, two NOT gate, three NOT gates. They’ve been connected one after
another such that the output for the first NOT gate becomes the input for the second
NOT gate. And the output for the second NOT
gate becomes the input for the third NOT gate.
Now, we’ve been told that the input
is set to one. So we need to find out what the
value of the output is. To work this out, let’s recall what
a NOT gate does. So a NOT gate, also known as an
inverter, takes anything into the input and reverses it.
So if the input is one, the output
becomes zero. And if the input is zero, then the
output becomes one. So fairly simplistic but very
useful. So with that in mind, let’s see
what happens when the input to this whole setup is one.
So this input one goes into the
first NOT gate and gets inverted to a zero. But then, the zero becomes the
input for the second NOT gate. And it gets inverted back to a
one. And then, this one becomes the
input for the third NOT gate getting inverted back to a zero.
And at that point, we’ve arrived at
the output. So the output is going to be
zero. Hence, for this particular setup of
three NOT gates connected in this way, if the input is one, then the output is
zero.
