Dimming reduces LED light output using linear or PWM methods. The linear method lowers current, avoiding electromagnetic interference, making it suitable for medical or research settings, but may reduce efficiency and requires fixture adjustments. PWM uses constant current pulses with variable width to control brightness without flicker. TRIAC dimmers, designed for incandescent lamps, need compatible LED drivers.
Flammable gas sensors, such as the MQ-5, are vital for detecting dangerous gases like propane, butane, and methane. These sensors use a sensitive semiconductor layer to react to gases, with components like a heating coil and gold electrodes ensuring accurate detection. They are critical in safety applications, including home gas detection and industrial use, offering early warnings of gas leaks and preventing explosions.
The optical system in LED fixtures creates the required light distribution using components like lenses, reflectors, and diffusers. Beam angle defines distribution type, distinguishing spotlights from general fixtures. Diffusers vary by light transmission and uniformity. Materials for optical elements include PMMA, silicone, aluminum, tempered glass, polycarbonate, and ABS, supporting 3D printing.
A sensitive amplifier with a filter is needed to process signals from ultrasonic or infrared sensors. The GL3274 IC, designed for infrared receivers, is used for this purpose. It operates at 4.7–5.3 VDC and features internal protection, band-pass and low-pass filters, and comparators. Replacing a photodiode with an ultrasonic receiver enables accurate distance measurement.
Low-voltage LED fixtures are commonly used due to their safety and cost-effectiveness. SELV standards define safe voltages for human contact, making such fixtures suitable for damp locations and areas accessible to children. Applications include architectural and track lighting, which benefit from smaller fixture sizes. Power over Ethernet enables efficient power and control in smart lighting systems.
