# Video: Identifying Circuit Symbols

Which of the following symbols represents an AND gate? [A] Symbol A [B] Symbol B [C] Symbol C [D] Symbol D

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### Video Transcript

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.