What characteristic differentiates low-pass filters from high-pass filters?

Low-pass filters are designed to allow low-frequency signals to pass through while attenuating high-frequency signals. This characteristic is essential in applications where it is desirable to isolate or maintain the integrity of lower frequency components of a signal, such as in audio processing, where you may want to eliminate high-frequency noise while preserving the lower bass frequencies. By allowing these low-frequency signals to pass unaltered, the low-pass filter serves its primary function effectively.

In contrast to this, high-pass filters are focused on allowing high-frequency signals to pass while blocking those that are lower in frequency. Therefore, the distinction between low-pass and high-pass filters is fundamentally about the range of frequencies they are designed to allow through versus those they attenuate.