Dimmer

When dimmer is called Power Control or Triacsteller to control the brightness of light bulbs such as stage lights, lamps or transformers for low voltage halogen lamps.

Dimmers can be conditionally used to control the power consumption of other consumers, similar circuits can be found in vacuum cleaners or hand drills, in which the power is to be changed.

Operation

Depending on the load characteristics there are different types of dimming. For incandescent and high-voltage halogen lamps ( 230 V) and a conventional transformer is dimmed with phase control. These consumers have a resistive or inductive load characteristics. Electronic transformers low-voltage halogen systems have a capacitive load behavior and must be controlled with circuitry more complex phase dimmers. There are also universal dimmer, the electronics detect the load characteristics and automatically adjusts the suitable starting method.

Fluorescent tubes and other gas discharge lamps can not be dimmed in this way, since the discharge collapses at low voltage and can not be re-ignited. Even before aborting the discharge, the cathode not reach at low voltage the necessary temperature and wear out faster. This electronic control gear (ECG ) can be used with brightness adjustment to ensure the required cathode temperature and produce a higher frequency, and thus prevent the demolition of the discharge. The units can be dimmed with a control signal (0 ... 10 V, EIB, DMX 512, DALI).

Control

The control of a dimmer is possible in several ways. Besides the known rotary knob modern devices can also be controlled via buttons today. In a Ferntastdimmer a short key turns the dimmer on and off a longer gating pulse causes a change in brightness. And the control by a control voltage is sometimes possible; in such dimmers control input is galvanically isolated from the mains.

Dimmer in the professional lighting technology

Via a control signal (as in DMX), the devices for each channel transmitted to an outputted from the light mixer value. In DMX that a value from 0 to 255 is typically According to this signal, the dimmer control to the headlamps. Depending on the configuration, the dimmer sit directly on the headlight housing or together or in groups in a rack. The connection to the headlights is then performed via load multicores, also known as Laka (Load cable). Frequently located between dimmers and Lakas a control panel ( patch panel ) to allow for different assignments of the multicores.

Stage lights are often not completely shut down, but only dimmed to darkness, so that when high taxes on full power, the inrush current is less and the filaments are not so heavily loaded. This can be made possible with most dimmers through a pre - heat function.

Dimmer in the household

In the living area there are dimmer in various forms

• Permanently installed in luminaires
• For installation in elements of the electrical installation, such as switch boxes, etc.
• For installation in DIN rail mounted distributor Modular installation device (MDRC )
• As so-called cord dimmer lights against mobile

Not every bulb is dimmable in its luminosity. The symbol for dimming is a lying solid triangle with one or two letters underneath. Also dimmers are marked accordingly:

• C for dimming with or for phase control dimmer ( capacitive load, for example, electronic low -voltage halogen lamps transformers ).
• L for dimming with or for phase control dimmers, which are suitable for inductive loads (eg wound, so conventional low voltage halogen transformers).
• R or light bulb icon: with these dimmers are only resistive loads ( incandescent lamps, heaters) dimmable.

Energy consumption

If an ordinary light bulb dimmed, the power consumption and consequently the energy requirement decreases. The lifetime increases may significantly since the filament temperature decreases; However, the efficiency of light production ( light output ) drops sharply. The brightness decreases when dimming from more than the power consumption (see also luminous efficiency and lifetime of light bulbs). By dimming the light also changes color, the color temperature drops and the light looks more yellow- orange than yellow-white.

Even with halogen lamps which are a bit more economical as compared to the incandescent lamp, the power consumption and consequently the energy needs while dimming decreases. However, the lifetime increases in abgedimmten operating only in the power range of about 99 to 80 percent. In the dimming range of 20 to 60 percent, however, collapses the tungsten halogen cycle process and the life sags significantly decreased.

If an incandescent or halogen lamp (such as a living room floor lamp ) anyway never operated under full load, then a majority of the required energy can be saved if it is replaced by a weaker lamp which has the same brightness undimmed state. The efficiency of a fluorescent lamp remains on the other hand, if it is dimmed with a suitable ballast, approximately constant ( or even increase it ), that means the power consumption drops with the brightness in the same way (even the color temperature remains fairly constant ).

Suppression

Due to the abrupt switching in phase dimmers and switching off in the phase cut dimmers creates very steep edges in the flow of current or voltage. After the Fourier transformation, these edges correspond in function of their rise and fall time ( slew rate ) a high frequency spectrum ( harmonics ) that can interfere with other devices such as sound and video equipment. To reduce this interference, snubber, chokes and filters are used which limit these steep flanks. Since these filters are expensive and heavy, is the suppression of the quality characteristics of a dimmer.

One finds dimmer almost without interference ( mostly household appliances with low power ), dimmer for event devices ( rise times in the range of some 10 microseconds) and equipment for use in recording studios and theaters with rise times of 500 microseconds, and more. The better the filter, the greater the rise times, so that the high-frequency noise components decrease.