Dimmer, is an electrical device that changes the luminous flux of a light source in a lighting device and adjusts the level of illumination. The purpose of a dimmer is to adjust the brightness of different lights. By reducing or increasing the RMS voltage, different intensities of light output are generated by the average power of the light. Although variable voltage devices can be used for various purposes, this regulation is aimed at controlling lighting.
There are three principles of LED dimmers
1. Pulse Width Modulation (PWM) digitizes the square wave of the power supply and controls the duty cycle of the square wave to achieve current control.
2. Constant current power supply regulation can easily adjust the magnitude of the current using analog linear technology.
3. Group control: Group multiple LEDs and use a simple grouping device to control them.
The above 1.2. two methods can be achieved by using an adjustable resistance knob for stepless control. Due to the maturity of PWM module technology, costs have been reduced. It is difficult to determine which method of flow control is being used from a price perspective. However, adjustable resistors themselves are not a very reliable component. Often, due to the entry of dust or the lax manufacturing process, there may be a momentary malfunction when operating adjustable resistors, causing the light source to flash. This flicker is less noticeable when using PWM mode, but more pronounced when using linear technology to regulate current.
No matter how the current is regulated, it can be changed to a touch switch or an independent group switch (such as a group controller or remote control) to control the lighting. This type of quality is more reliable and has a much longer service life. It is necessary to use adjustable resistors for delicate lighting control. It is recommended to use high-quality adjustable resistors (usually costing a few to 10 yuan).
Whether LED is driven by step-down, step-up, step-down/step-up, or linear voltage regulator, the most common thread connecting each driving circuit is to control the output of light. Currently, there are only a few applications that only require simple functions to turn on and off, and the vast majority require fine-tuning the brightness from 0 to 100%. The two main solutions for photometric control are linear adjustment of LED current (analog dimming) or switching the driving current back and forth from 0 to the target current value at high frequencies that are imperceptible to the naked eye (digital dimming). Using Pulse Width Modulation (PWM) to set the cycle and duty cycle may be the simplest way to achieve digital dimming, as the same technique can be used to control most switching converters.
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