Activation Functions in DNN

In artificial neural networks, activation function plays an important role in determining the output of the neuron. To make it sound more realistic, we can simply compare the activation function to the biological neurons which fire the signal to other connected neurons. Basically, the activation function maps an output value between the value 0 and 1. Guess Why?, Because the neuron has a value which is not confined to a scale, making it unclear when to fire. Thus this value from neurons is mapped to a scale to understand as in when to fire (as in case of biological neurons). Where w is the weight of a neuron, x is an input and b is bias value.