Valovoimasäätö

Valovoimasäätö, known in English as light intensity control or dimming, is the process of adjusting the brightness of a light source. This can be achieved through various methods, fundamentally altering the amount of light that reaches the observer or a sensor.

One common method is amplitude modulation, where the electrical power supplied to the light source is varied. For incandescent bulbs, this involves reducing the voltage, causing the filament to heat less and emit less light. For LED lights, dimming is often achieved by pulse-width modulation (PWM). In PWM, the LED is rapidly switched on and off. The perceived brightness is determined by the ratio of the "on" time to the "off" time, known as the duty cycle. By changing the duty cycle, the average light output is controlled.

Another technique is by controlling the current. Some light sources, particularly LEDs, are sensitive to the current flowing through them. Reducing the current directly reduces the light output. In some systems, filters or shutters can also be used to physically block or reduce the amount of light emitted, although this is less common for electronic dimming.

The purpose of valovoimasäätö is multifaceted. It allows for creating specific lighting atmospheres, reducing energy consumption by not operating lights at full brightness when not needed, and extending the lifespan of some light sources. It is a fundamental aspect of lighting design in homes, theaters, public spaces, and many industrial applications. Different dimming technologies offer varying degrees of efficiency, compatibility with different light sources, and control capabilities.