As in the last article we were discussing Perceptron. Now we will discuss the **Sigmoid Activation Function. **As the name represents its shape will be somewhere similar to sigma **σ**.

The above-mentioned figure is the graph of the sigmoid activation function. It provides the output from 0 to 1. The sigmoid activation function can be described by the following expression

First let’s assume that we put three values (0, +∞, -∞) turn by turn in the above-mentioned expression. First, let’s put 0 then the expression will become

After putting the value 0 we got the output of sigmoid function as 0.5. Now let’s put the value of -∞ in the expression of the sigmoid function

Therefore when we put the value of x as-,** **the output will be 0 as shown in the graph above. Now let’s put the value of +** **in the sigmoid function

Here comes the output when we put the value of x = +** **which can also be seen in the graph above. We will come towards the derivation of the sigmoid function in the next article.