1. Incandescent bulb and halogen lamp

   These types of light can basically be dimmed using triacs. The dimming response curve is quite smooth and very apparent. But since incandescent lamps are being phased out by law, most of these are being replaced instead by CFL, whilst halogen lamps will be replaced by LED lamps.

2. Fluorescent lights

   These are very common and can be found in a plethora of places such as offices, retail stores, factory floors, classrooms and many other public places.

   Rarely are they found as dimmable lights, and they being replaced by T5/T8 energy saving fluorescents, and also being replaced by LED fluorescents.

   T5/T8 fluorescents can be dimmed using electronic dimming ballasts, the most common type are those adjustable from 0 to 10V, often these types of ballasts will not turn off completely even at 0V, and a faint glow will still be visible. If one wants to truly have the lights off, then a switch is still needed to completely cut of the power.

   Fluorescent lights that are dimmable in this manner is very rare, and even when present, their main purpose is to save energy and not for use as mood lighting.

3. CFL – Energy Efficient Compact Fluorescent Lamps

   These are commonly found in residences, and used to replace traditional incandescent lights, they are not very rarely used in dimming applications, but still they do exist, and the method used is by using triacs. Situations like this require that the CFL type specifically be marked as being “dimmable”. Otherwise, using a triac is not guaranteed to be able to dim the lamp.

   In practice, the dimming effect is quite weak, and at low levels, the light will flicker. When dimmed to its lowest level, it will turn off completely.

   Of course, having this dimming capability versus one without will increase its costs quite significantly.

4. LED lamps

   These are used to replace all sorts of traditional lamps including incandescents, fluorescents and halogens; and may even replace strip lights and mercury lights (street lights, park lights). The form that LED lamps can take are innumerable and they come in all shapes, sizes and color temperatures. They have a wide variety of power supplies (a/c, a/c dimmable, d/c constant current, d/c constant voltage, d/c constant current dimmable, d/c PWM dimmable); and they need to come with a wide range of wattages and d/c voltages. Some have the power supply built in (outwardly appearing as a/c), while others require an external power supply, and some emphasize that they are dimmable, or there may be any number of combinations of the above. Faced with such a multitude of possible choices, making sure that one obtains one that is dimmable and the matching type of dimming power supply becomes a job for an expert.

   Purely from the point of view of control, one type is a/c dimmable using a triac, while the other is 0 to 10 VDC. Each requires the appropriate type of lighting controller, as these are very different technologies.

   With dimming, the emphasis may be for mood creation, or it can be mainly to save on energy.

As can be surmised from the above, when dimming is desired, selecting the right type of lamp is the first step, and the second step is a matching dimming driver, the third step is to get a controller that will work with the driver. If a non dimmable lamp is used, then no dimming is possible even if both the power supply/driver and controller having dimmable features.
What venues are suited for dimming?

1. For setting the ambience such as the chandelier of a great hall. The numerous smaller lights use energy saving lamps which are on/off controlled only.
2. Also for setting the ambience. The lights are meant to either be fully on or off, but with the capability to switch the lights by a gradual transition instead of an abrupt change, the purpose of which is also to create a more elegant and classy atmosphere. Halogen lamps are mostly used in this situation, if LED lamps are used instead then the cost increases substantially.
3. Energy saving fluorescent lighting: Fluorescent lighting for large spaces, sometimes of the LED type, which require different lighting levels at different times to save on energy.