What is a Band Pass Filter?

A Band pass filter combines the characteristics of the High Pass and Low Pass Filters. 

The Band pass Filter, as the name suggests, allows only signals of a particular band or range of frequencies to pass through.  All other signals are blocked or shorted.  Band Pass Filter

Band pass Filters can be made by connecting a high pass filter in series to a low pass filter or vice versa. 

A Band pass filter can be made by connecting an inductor in parallel to filter the low frequency components which lie below the desired frequency.  Another inductor in series will then block the high frequency components which lie above the desired frequency.

Likewise, the Band pass filter can also be made using capacitors as in the second figure.  Here, the first capacitor filters the high frequency components and the second capacitor in series blocks the low frequency components.