A dimmer, regulator, attenuator or dimmer, serves to regulate the energy in one or more spotlights in order to vary the intensity of the light they emit, when the properties of the lamp make it possible.

Currently, the most used circuits include the ignition function when the voltage "crosses zero". The decrease in the effective value in the bulb is achieved by cutting the signal at the moment of rise at the chosen point (if we cut the signal when the wave reaches 60 V p.e. it will turn on very little, while if we cut it when it reaches 200 V it will turn on almost to the maximum).

There are more complex systems capable of regulating the lighting flow for other types of lamps (fluorescent, low consumption, etc.) but they are more complicated.

Some dimmers can be controlled remotely through special drivers and protocols. In the case of stage lighting, one of the most used protocols is DMX (Digital MultipleX), which is a communications protocol used to control stage lighting, or DMX512, which allows the intensity of conventional lights to be synchronized with special effects lights, smoke machines, etc.