A band-pass filter is an electronic circuit that allows signals within a specific frequency range to pass through while blocking frequencies outside that range. This is useful in various applications, such as audio processing and communication systems, where it is important to isolate certain frequencies from noise or interference. These filters are characterized by their lower cutoff frequency and upper cutoff frequency, defining the bandwidth of frequencies that can pass. Band-pass filters can be implemented using passive components like resistors and capacitors, or active components like operational amplifiers, depending on the desired performance and application.