설명The HHSL402SD is a generalpurpose handheld instrument that measures the noise level of an environment or the sound level produced by a piece of machinery. Using an integrated 13 mm (0.5") condenser microphone, the meter can measure sound levels from 30 to 130 dB with a resolution of 0.1 dB and show the results on a front-panel liquid-crystal display. Several features and capabilities enhance the meter’s versatility. Among them are autoranging, the ability to hold readings and display maximum and minimum readings, and user-settable measurement parameters such as frequency weighting (using the “A” and “C” standards) and time weighting (fast or slow). Because it is microprocessor-based, the HHSL402SD can make full use of the portability, reliability and large storage capacities that SD memory cards offer.