A, C and Z Weighting Explained: Which Sound Level Meter Setting You Actually Need
A guide to the three common frequency weightings on sound level meters, what they are for, and the mistakes that make readings meaningless.
Read Article→Learning Center
Plain-language explanations of the measurements, sensors and numbers behind environmental monitoring.
Oscilloscope Not Working: Why Your Scope Shows Nothing and What to Check
Most 'dead' oscilloscopes are set to the wrong coupling, trigger or timebase, or the probe ground is not connected; this page walks the checks in order.
Read Article→Why noise rules are written around a time averaged level
Noise rules use an energy averaged level because harm and annoyance depend on total acoustic energy received over a period, which no instantaneous reading can represent.
Read Article→What instrument class means on a sound level meter
Class on a sound level meter names a tolerance envelope that runs across the whole frequency range, so Class 1 and Class 2 differ mainly in how far the instrument may deviate away from one kilohertz rather than at it.
Read Article→Why 0.1 dB resolution and 2 dB accuracy sit on the same sound level meter
Resolution is the smallest step a display can show and accuracy is how far the whole reading may sit from the true level, so a meter can legitimately show tenths while being uncertain by two decibels.
Read Article→Can a particle counter tell you a room meets a guideline?
A handheld particle counter can indicate whether a room is likely to be within a guideline but cannot demonstrate compliance, because published limits are averages over hours or classifications with defined sampling plans and traceable instruments.
Read Article→Why two particle monitors in one room disagree
Most disagreement between two particle monitors in the same room comes from the two instruments sampling different air, different calibration aerosols and different humidity response, rather than from one of them being broken.
Read Article→What a 0.3 micron smallest channel leaves out of the count
A smallest channel of 0.3 micron is an optical limit rather than a physical one, and the particles below it are invisible to the instrument while often outnumbering everything it does count.
Read Article→Why flow rate decides whether a particle count can be repeated
A particle count only becomes a concentration once it is divided by a sampled volume, so a pump whose flow is unknown or drifting turns every reading into an unrepeatable number.
Read Article→Particle counts and mass concentration: two numbers from one sensor
A particle counter observes counts per unit volume and calculates micrograms per cubic metre from them, so the first figure is a measurement and the second is a model built on assumed particle density and shape.
Read Article→Reading a humidity record from a damp investigation honestly
Relative humidity is a ratio whose denominator moves with temperature, so a record can show a dramatic overnight rise with no extra moisture in the building at all, and the honest reading works from dew point and surface temperature instead.
Read Article→Why a replaceable humidity sensor extends an instrument life
The polymer element in a humidity sensor is a consumable that degrades through contamination and condensation while the electronics around it stay perfectly serviceable, so a design that lets you swap the element turns a disposable instrument into a maintainable one.
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