RGB LED Sources

RGB LED Source

(Product ID: LM2X-DMHP-RGB)

The RGB LED is a 2-inch, air-cooled LED light source that provides three-color (Red, Green, and Blue) outputs. This LED is typically used for Particle Shadow Velocimetry (PSV) systems to illuminate small seed particles in a flow field to measure velocity and particle density. The RGB LED has three BNC inputs to control the timing and pulse width of each of the output colors from an external pulse generator. The pulsed LED operation is controlled by applying a TTL voltage to the external BNC(s) on the module. The rise time is less than 200-ns and the fall time is less than 100-ns and the duty cycle is 5%. The light distribution from the unit is approximately Gaussian for distance greater than 18 inches from the source.

PSV is a novel technique that shares many of the attributes of microPIV and Forward Scatter PIV (fsPIV). It utilizes low-power pulsed LEDs to measure the displacement of seed particles in a flow. PSV images can also be used to characterize particle parameters such as size and shape. Any pulsed light system can be used as the light source; however, LEDs are particularly well suited since they can be over-driven in a short-pulse mode to produce intense sub-microsecond light pulses. Furthermore, the use of LED’s combined with a high speed camera results in a high-speed system with bandwidth of 10’s of kHz. Because the technique does not rely upon weak-particle light scattering, lasers are neither necessary nor recommended and the RGB LED can be used in its place.