Which of the following symbols
represents an AND gate?
Okay, so in this question, we’ve
been given four fairly similar-looking symbols and we need to figure out which one
is representing an AND gate. Now in each one of these symbols,
we can see that the gate in question has two inputs and one output. And as we know, an AND gate has two
inputs and one output. But because each one of these
options has two inputs and one output, we can’t use that as a determining
factor. Instead, we can use a memory
technique that tells us what the symbol for an AND gate should look like. We can recall that the symbol for
an AND gate should look like the letter D. And this is quite easy to remember
because the word AND has a D in it. So based on this information, we
can go through options A to D.
Let’s start with option A. Now option A looks fairly
promising. We can see that the D shape exists
in the symbol. However, because there’s this
little circle after the D shape, we know that this cannot be representing an AND
gate. Because the little circle
represents something else. It turns it into something known as
a NAND gate. But anyway, so option A is not the
answer to our question. Looking at option B then, we see
that we’ve got almost a D shape but that the left-hand edge is curved. And so, that does not look like the
letter D. And hence, this is not the answer
to our question either.
Now the same is true for option
C. It’s got almost this D-shape but
this curve on the left side. And as well as this, it’s got the
circle on the right. So it cannot be the symbol for an
AND gate whereas option D gives us this D shape for the AND gate. And that’s all it is. It doesn’t have a little circle on
the right or a curve on the left-hand side. And so, option D is the symbol that
we’re looking for. And hence, we can say that this is
the symbol which represents an AND gate.