Selection Guide

Noise dosimeters and sound level meters both measure sound, but they serve different purposes. A sound level meter measures sound levels at a specific location or near a particular source, while a noise dosimeter is typically worn by a worker to continuously record personal noise exposure over a work period. This article explains their key differences and when to use each instrument.

RPM and m/min are both commonly used speed parameters in industrial equipment, but they describe different types of motion. RPM represents rotational speed, while m/min represents linear speed. This article explains their definitions, differences, conversion relationship, measurement methods, and practical applications involving motors, rollers, conveyor belts, and production lines.

A contact tachometer can measure not only rotational speed but also the linear speed of belts, conveyors, rollers, and other moving surfaces when fitted with a surface speed wheel. This article explains the measurement principle, conversion between RPM and linear speed, correct operating procedures, and the main factors affecting measurement accuracy.

The decibel is not a direct physical unit of sound magnitude, but a logarithmic way of expressing the ratio between two quantities. Because acoustic quantities can vary over an extremely wide dynamic range, a logarithmic scale makes sound levels much easier to represent, compare and calculate. This article explains why decibels use logarithms and how common dB changes relate to sound pressure, sound intensity and sound power.

Sound pressure, sound intensity, and sound power are fundamental acoustic quantities, but they describe different aspects of sound. Sound pressure represents local pressure fluctuations at a measurement point, sound intensity describes acoustic energy flow per unit area, and sound power represents the total acoustic energy emitted by a source per unit time. This article explains their differences, relationships, measurement methods, and practical applications.

dBA is a sound pressure level measured using A-frequency weighting. It adjusts different frequency components according to the frequency sensitivity of human hearing. This article explains what dBA means, how A-weighting works, how dBA differs from dB and dBC, and why sound level meters commonly use dBA for environmental and occupational noise measurements.

Sound and noise share the same physical origin: mechanical vibrations that propagate as sound waves. The difference is largely determined by context and impact. A sound may be considered noise when it is unwanted, disturbing, or interferes with work, rest, communication, or well-being. This article explains the relationship between sound and noise, the key acoustic parameters involved, and why objective measurement is important.

Sound is a mechanical wave generated by vibration and transmitted through a medium such as air, liquid, or solid. Understanding how sound is produced and propagated provides the foundation for learning about sound pressure level, decibels, frequency weighting, noise measurement, and acoustics. This article explains the basic principles of sound sources, wave propagation, frequency, wavelength, sound pressure, and sound measurement.

Tachometer resolution indicates the smallest change in rotational speed that an instrument can display or distinguish, typically expressed in RPM. A smaller resolution value provides finer indication of speed changes, but higher resolution does not necessarily mean higher accuracy. This article explains tachometer resolution, its relationship with accuracy and measuring range, and how to choose an appropriate resolution for different applications.

Non-contact laser and photoelectric tachometers often require reflective tape on the rotating surface to create a clear and repeatable optical signal. This article explains how reflective tape supports reliable RPM measurement, where it should be applied, common sources of measurement error, and when it may not be required.

A laser tachometer is a non-contact rotational speed measuring instrument. It directs a laser beam at a reflective marker on a rotating component, detects the periodic reflected-light signal, converts it into electrical pulses, and calculates rotational speed in RPM. This article explains the complete measurement process, from laser emission and optical detection to pulse processing and RPM calculation.

A contact tachometer measures rotational speed by placing a contact tip or measuring wheel directly against a rotating shaft or moving surface. Mechanical motion is transferred to the instrument, converted into electrical pulses by an internal sensor, and processed to calculate RPM or linear surface speed. This article explains its operating principle, measurement process, common contact attachments, accuracy factors, and correct use.