A band-pass filter is an electronic device 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 telecommunications, where it is important to isolate certain frequencies from noise or interference. In a band-pass filter, two cutoff frequencies define the range: the lower cutoff frequency and the upper cutoff frequency. Signals below the lower cutoff and above the upper cutoff are attenuated. This type of filtering is commonly used in devices like radio transmitters and receivers to ensure clear communication by focusing on desired signals.