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Units of measure

Driver / transformers

Dimmer

Dimming mode and signals

Light sources: types and specifications

Foundations of electrical technology

Classifications

Dimming signal through variation of the voltage between 0 and 10 Volt DC. Normally this variation is achieved using a remote potentiometer or a building automation control panel; to operate, it requires two additional cables connected to the standard power supply.

1-10V

Indicated also as AC (for Alternating Current), it is a current whose direction and polarity periodically change. The frequency with which this occurs is measured in Hertz.

Alternating current

Basic International System unit of measure for the intensity of an electrical current; it refers to a real power consumption. The measurement is the relationship between wattage and voltage (A= W/V).

Ampere (A)

This is not a signal for dimming, but a system to automate/control various utilities; its name derives from the fact that it connects various devices through a bipolar cable referred to as BUS, which transfers the encoded information to the technical devices, according to modes called protocols, through the use of actuators and interfaces. The most widely used protocol is KN (Konnex).

The base unit in the International System of Units referring to luminous intensity, that is, the light concentration/ power emitted by a light source in a particular direction on a solid angle (steradian). This value is irrespective of the distance at which it is measured. Candelas are calculated from lumens according to the following formula: 1 lm/sr (lumen by steradian) = 1 cd. Usually the luminous intensity of dichroic bulbs is indicated in candela specifically because it is directed in a particular light cone.

Candela (cd)

This category covers units where risk prevention is entrusted to the main insulation on the wires and to earthing or grounding of the accessible metal parts of the system.

Class 1

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This category covers units designed so that they do not require a safety connection to electrical earth or ground. Often cited as units with double insulation, such devices are identified by a symbol containing two concentric squares.

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Class 2

This category covers units for which the power supply does not exceed the safety extra-low voltage (SELV).

Class 3

Generally measured in degrees Kelvin (K), it commonly refers to the colour tone emitted by a light source.

Colour temperature

This is usually set into the recessed wall box of the buildings own system. It takes up the space of one or two modules, like a normal switch, and is used to adjust limited resistances and powers.

Connector socket-mounted dimmer

This current is generated in such manner as to keep the intensity steady in time. In most cases, the LED modules are interconnected in series and powered by direct, constant current.

Constant current

This current is generated in such a manner as to keep the intensity steady in time. The voltage of the household network is transformed into low voltage (usually a value of 12V) through the transformers that keep it constant to enable the operation of low voltage light sources. For instance, various versions of the Mini Giulietta are powered in constant voltage at 24V DC or at 5V DC (USB version).

Constant voltage

See “colour temperature”.

Cool, neutral and warm white LED

See RA.

CRI (Color Rendering Index)

A standardized protocol used to control luminaires. With it, up to 64 devices can be controlled, dividing them into sections and creating scenarios that are easy to modify through the system controller. To operate, it requires just two wires connected in parallel between the devices.

DALI (Digital Addressable Lighting Interface)

Device used to adjust the intensity of the light produced by a luminaire. There are different types of dimmers; they can be installed on the lamp's power supply cable, integrated into the transformer/power supply unit or be part of the building's own electrical system. When supplied, the Catellani &amp; Smith pricelist indicates the type of dimmer and the dimming modes for its lamps.
The end customer/designer is responsible for checking the compatibility of our products with the electrical system they will be plugged into. The use of incompatible dimmers could damage the luminaire. Any damage caused by the installation of incompatible dimmers will not be covered by the guarantee. Please note that specific dimmers for halogen lamps may not be compatible with LED light bulbs; it is therefore advisable always to choose specific dimmers for LED light bulbs (see section 5.5, p. 217- 218).

The lamp regulation device is integrated into the transformer itself. It can recognize various signals and dimming protocols depending on its own inherent characteristics. Typically used with building automation systems, it requires an in-depth compatibility study to ensure correct communication with the systems own control units.

Dimmer integrated into the transformer/power supply unit

The dimmer memory saves the status of the luminaire after a temporary interruption in the power supply - e.g. if the switch is tripped, a safety device (automatic cut-out switch) activated or in case of a power blackout (see sections 3.3.1 to 3.3.4).
Some devices have a memory if the switch is tripped, but lose it in the event of a power blackout; this means that, once the power returns, the lamp may be turned on or off depending on the characteristics of the dimmer.

Dimmer memory

Also indicated as DC (for Direct Current), its intensity and direction remain constant in time. It is widely used in electronics, for example in powering LEDs. In electricity distribution, for practical purposes, it is preferred over alternating current.

Direct current

The term domotics indicates “building automation”, that is the system used to control all services in a building, designed to improve comfort, safety and energy savings in the latest generation buildings. Whether directly or through the use of remote controllers, smartphones and tablets, it can be used to control lighting, heating, video surveillance and many other household electrical devices as long as they meet the compatibility requirements and are adequately interfaced. While performing the same functions, each domotic system differs in terms of the protocols and signals used to enable inter-unit communication.

Domotics

Drivers are power supply units for LED diodes. They enable the correct connection of a limited number of diodes, the number depending on the power rating of the power supply unit.

Driver

This indicates the quantity of current passing through a section of wire in a given unit of time. It is measured in amperes, a fundamental International System unit of measure.

Electrical current

Difference in electrical potential detected at the ends of a wire. It is measured in volts.

Electrical voltage

Classification of luminaires according to power consumption and luminous efficiency. The class rating for luminaires, ranging from A to E, is indicated on the easy-to-consult standardized label. In compliance with EU regulation no. 874/2012, luminaire manufacturers are required to produce a label for each luminaire manufactured and make it available telematically for consultation.
The energy labels for each of our products can be downloaded directly from our website www.catellanismith.com and are specified for each model. Retailers are required to print and display this label for every product displayed in their showroom.

Energy efficiency class

Typical of table or standing lamps; the device is integrated into the lamp's power cable. The light adjustment is performed with a cursor or pushbutton. This type of dimmer cannot be adjusted by remote control, domotic system or addition electrical system as this would irreparably compromise the luminaire.

External cable-mounted dimmer

Lamp that emits indirect light. Normally such lamps are tubular and are available in different colour temperatures. To function, these lamps require a transformer (ballast) and thus cannot be connected directly to the power mains. In the compact version (best known, most widespread of the so-called energy saving lamps), the ballast is incorporated.

Fluorescent lamp

Direct evolution of the incandescent lamp, this lamp offers greater efficiency and longer life as well as better colour yield. They can be used with power from the mains and 12V power supplies and are available in cold and neutral colour temperatures. Low efficiency halogen lamps will be banned as of 2016.

Halogen bulb

Unit of measure for electrical frequency indicating how many times an event occurs within a second.

Hertz (Hz)

Also called descending phase cut-off, this technology was created to adjust inductive loads (transformers for low voltage lamps). Quieter than TRIAC technology, this control does not require additional cables to operate.

IGBT/trailing edge/Reverse phase control

Circuit in which the components are connected to one another so that the current fiows over a single path. In the case of two-pole components, the end of one component is connected only to the end of the next component. LEDs are almost always connected in series, Catellani &amp; Smith applies particular countermeasures to ensure that the failure of one LED will not compromise lamp function.

In-series connection

Lamp that produces light by heating a tungsten lament until it is made red hot (incandescent) by the electrical current owing through. The light emitted tends to be warm. Since 1st September 2009, the European Union has applied a gradual ban on this type of lamp, replacing it with sources that reduce environmental impact and offer greater lighting efficiency and longer life.

Incandescent bulb

Breakdown, established by the IEC, of the countermeasures applied in an electrical appliance to prevent the risk of electrocution. There are 3 main classes of insulation:

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Insulation class

Physical or virtual device that enables communication between one or more luminaires with different types of communication protocols. For instance, a KNX-Dali interface is a device that enables a home automation system with KNX protocol to communicate with a driver with Dali protocol.

Interface / actuator

Internationally recognised code, defined by CEI EN 60529/1997, that rates electrical appliances according to the degree of protection against intrusion of solid and liquid objects. The first digit indicates protection against solids on a scale of 0 to 6, where 0 means "no protection" and 6 "totally protected against dust"; the second indicates protection against liquids on a scale of 0 to 8, where 0 indicates "no protection" and 8 "protected against the effects of continuous immersion". Unless otherwise specified, all our products have a protection rating of IP20 (indoor use).

IP (Ingress Protection) rating

International System unit of measure for temperature; in lighting design it refers to the colour tone of the light emitted. The LEDs we use are generally warm white (average 2,700 K).

Kelvin (K)

This is not a signal for dimming; it is the rst open building automation (domotics) protocol approved as a European and world-wide standard. It is used to manage, control and operate entire buildings, lighting systems included, through the use of actuators and interface (lighting interface) which make the protocol comprehensible to the various luminaires by sending them the correct signal for dimming.

KNX/EIB

The lamp is on, regulated to the last position set by the user. Where featured, the dimming memory is retained when the lamp is turned on or off using the switch included in the dimmer device; it may be deleted if a remote switch is tripped, for instance from a controlled socket.

Last step memory

Given their high luminous efficiency, life and colour rendering, in recent years LEDs have become the light source of choice for manufacturers and lighting designers and for consumers who are increasingly sensitive to energy savings and environmental protection. The light emitted by the LEDs we use tends toward the various tonalities of white: cool white, neutral white and warm white.
According to market availability, Catellani &amp; Smith pledges to ensure that the LED light sources in its own luminaires can be replaced (see section 5.12 LED life cycle).

LED (Light Emitting Diode)

LED bulbs are replacing traditional incandescent bulbs (section 5.1) or halogen bulbs (section 5.2) since they are preferable in terms of efficiency and energy savings (energy classes A to A). They usually have the same shape and socket as traditional bulbs (e.g. E27, E14, GU10, GU5.3 etc.), integrating LED diodes and electronics (driver) required to guarantee operation. Currently there are no official technical rules that regulate the operation of this type of bulb. Since the behaviour of light bulbs with integrated electronics is different from that of simple light bulbs, most manufacturers provide lists of compatible dimmers, which allow you to select the most suitable dimmer. It is advisable always to use transformers and dimmers specific for LED bulbs and to check whether they are compatible and operating properly. When using traditional dimmers, it is advisable always to check that they have been tested and approved by the manufacturers of the light bulbs you intend to use and the maximum number of LED bulbs that can be dimmed. In fact, these dimmers work with high minimum loads and do not read the low loads of LED bulbs: the electronics integrated in the light bulbs must be able to ensure the dimmer perceives the minimum load required. Therefore a dimmer that is not designed specifically for LED light bulbs might dim a smaller quantity of bulbs than a LED- specific dimmer would (e.g. a generic 300W dimmer can dim up to a maximum of 10 x 4 W LED light bulbs for a total of 40W, while a LED- specific dimmer with a maximum power of 100W can dim up to 25 up to a maximum of 100W precisely. LED lamps also contain various electronic components that, in unfavourable conditions, may generate acoustic noise. Catellani &amp; Smith uses, recommends and checks the high-quality LED light bulbs of the leading suppliers on the market (e.g. Philips, Osram, Soraa, Idealed, etc.) and cannot guarantee the proper functioning of its luminaires with low-quality LED bulbs or those from unknown LED bulb manufacturers.

LED bulb

As opposed to conventional light sources, LEDs do not "burn out", rather, in time, the intensity of the light emitted declines. Although there is as yet no standard defining the life of a LED, its life is generally deemed terminated when the light emitted declines to 80% of the initial level. Since it is not possible to test a LED until total extinction, LED manufacturers are required to state the parameters used to estimate time before the luminous flux of a LED light source falls below that percentage. The life of a LED is generally counted in hours; however, this always depends on the type of use: continuous (typical of a business where the lamp remains on all the time) or occasional (as in households where the lamp is on for a few hours a day). For example: if a LED guaranteed for approximately 30,000 hours remains on 24 hours a day, it will last 3 years while, if it is only on for 3 hours a day, it could last up to 40 years.

LED life cycle

This term refers to the voltage at which the electrical current is distributed nationally. The voltage can vary from one country to the next; generally, in Europe, the line voltage is 220/230V while it is 110V in the United States.

Line voltage

Unit of measure that corresponds to the photometric equivalent of a watt. It refers to the luminous lux (in other words the quantity of luminous energy emitted by a light source) visible by the human eye. In general, what relates the intensity with the lux (candela with lumen) is the angle of emission of light. To calculate the lumen/ candela conversion, you have to convert the radiation angle of the beam (supplied by the manufacturer in degrees) in a solid angle (unit of measure: steradians). Thus we can calculate, for instance, that a LED with an intensity of 2.4 cd and a diffusion angle of 120 ° will present a lux of about 7.5 lm.

Lumen (lm)

Unit of measure for illuminance of the luminous ux (lumen) per unit area. In other words, it indicates the visible lux (lumen) per square metre at a particular distance. The greater the distance between the source and the surface, the lower the lux detected.

Lux (lx)

On the chromaticity diagram of the CIE (International Commission on Illumination), MacAdams ellipses refer to the regions defining the human eyes' ability to distinguish the different colours at the centre of the ellipse. They are used as an index in selecting the colours for LED diodes.

MacAdams ellipse

The lamp is off.

Memory 0%

The lamp is on, adjusted according to a percentage set by the dimmer manufacturer.

Memory 1-99%

The lamp is on at max power.

Memory 100%

These lamps have good chromatic performance and rather high efficiency which makes them suitable for many applications. They produce a warm light although there are some drawbacks such as the time required to reach maximum illumination and needed to turn them back on, as well as the fact they cannot be dimmed. Moreover, they require a ballast to operate so they cannot be connected directly to the mains voltage.

Metal halide lamp

This type of dimmer is integrated into the building's electrical panel; it is designed to adjust different types of loads and very high powers. Lamp compatibility must be checked before this type of dimmer can be used.

Panel-mounted dimmer (din module)

Circuit in which the components have the same poles connected to a different wire. All positive poles are thus connected together and likewise all negative poles are so connected. A typical example are ceiling lamps that continue to function even if one of its many bulbs should fail.

Parallel connection

Electrical device able to convert alternating current (AC) into constant current (CC); generally it also modifies voltage and current intensity.

Power supply unit

Dimming achieved with a normally open pushbutton to be embedded into the system. The signal reaches the lamp's transformer which contains the dimming equipment. To be able to function, it requires two additional wires running to the power supply unit.

PUSH

Pulse width modulation is a type of digital modulation that requires actuators to vary the illuminance of a given environment continuously.

PWM (pulse-width modulation) signal

Often confused with colour temperature, colour rendering is the qualitative evaluation of the chromatic aspect of the objects being illuminated. In other words, it is a measurement of how “natural” the colours of the objects appear. The value is established as a percentage according to the CRI (Colour Rendering Index).

RA (colour rendering)

This type of dimmer is integrated into the lamp so adjustments can be performed by touching the sensitive part of the luminaire or by using pushbuttons integrated into the structure of the lamp itself. This type of dimmer cannot be adjusted by remote control, domotic system or addition electrical system as this would irreparably compromise the luminaire.

Touch dimmer or pushbutton incorporated into the lamp

Electrical device used to modify voltage and current intensity. There are different types and various wattages. The most common distinction is between electronic and toroidal (or mechanical). Although toroidal transformers are dimmable with dedicated dimmers, it is advisable to choose an electronic transformer in case you want to connect the luminaire to a dimmer or to home automation systems. Compatibility with dimmers or home automation systems must be checked by the customer or designer, since the use of incompatible devices could damage the luminaire itself. Any damage caused by the installation of incompatible dimmers will not be covered by the guarantee. Please note that specific transformers for halogen lamps may not be compatible with LED light bulbs; it is therefore advisable always to choose specific transformers for LED light bulbs (see light sources/LED bulb).

Transformer

Also called ascending phase cut-off, this technology was created to adjust resistive loads (mainly incandescent lamps or network voltages). The latest TRIAC dimmers can dim LED lamps although they must be declared compatible with this type of adjustment. It does not require additional electrical wiring to function.

Triac/Leading edge/Forward phase control

There are different types of dimmers for different purposes. Below is a list of the most common.

Types of dimmers

Derived unit of power in the International System of Units for the measurement of difference in potential; it usually refers to the voltage of the electrical system (230V, 110V, 12V, 24V) or to the supply voltage of the light sources.

Volt (V)

Difference in potential detected at the two ends of a wire, in lighting design the important value is that of the wire carrying electricity from the transformer to the lamp. It determines the maximum length of the wire which must remain within set maximum limits or the lamp will lose luminous efficiency.

Voltage or supply drop

Unit of measure of the International System of Units referring to electrical power (W = V * A) and so to actual consumption. For instance: a LED board with a voltage of 2.85 volts powered at 350 mA consumes about 1W.

Watt (W)

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