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An optical particle counter draws air or liquid through a laser beam and measures scattered light to count and size particles.
For the full breakdown, see our best Air Particle Counter guide.
An optical particle counter (OPC) pulls a sample through a focused beam and turns each particle’s flash of scattered light into an electrical pulse. You can think of how an optical particle counter works as a chain of five events: steady flow, laser illumination, scattering, detection, and pulse analysis.
How the Measurement Works: From Laser Beam to Size Bin
The measurement starts with controlled flow. A pump draws the air or liquid sample through a nozzle, often an isokinetic probe, so the sensing chamber sees a steady, representative stream.
Inside the chamber, a focused light