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LEDs FAQ

Q: What are LEDs?
A: A Light Emitting Diode (LED) is a semiconductor device that emits narrow spectrum light when electrically biased in the forward direction. The colour of the emitted light depends on the chemical composition of the semiconducting material used.

Q: What are the benefits of using LEDs as a light source?
A: The main benefits of using LED light sources are:

Q: What is the difference between single colour LEDs and RGB LEDs?
A: An RGB LED consists of multiples of three LEDs (red, green and blue). A multitude of different colours can be created by mixing various intensities of these three basic colours. Single colour LEDs are available in many different colours however the colour is fixed and cannot be changed.

Q: What is the real life of LEDs and why is there such variation claimed (50,000 to 100,000 hours)?
A: Every LED experiences a gradual and permanent reduction in light output during operation. PHILIPS Lumileds classify a failed LED as one whose lumen output has reduced to 70% of the initial output. It should be noted that the human eye is insensitive to small changes in illuminance levels and that a decrease in output of approximately 50% is needed in order to create noticeable change. (Source: PHILIPS Lumileds, Application Brief AB25). All Garden Q luminaires are designed to keep the junction temperature well below maximum rated values in normal operating conditions, even at elevated ambient temperatures. To achieve optimum life, LED luminaires should not be operated in direct sunlight, therefore it is recommended a PE cell be included in any exterior LED luminaire installation.

Q: What is the relationship between the temperature at which the LED runs and its life span?
A: Running an LED above the manufacturer’s recommended junction temperature will result in an accelerated reduction in light output. Since the long life of LEDs is a key benefit, it is essential for the temperature of the LED junction to be managed correctly.

Q: How consistent are particular colours of individual LEDs?
A: During the manufacturing process LEDs are binned (sorted) according to colour, forward voltage and luminous flux. Garden Q uses binned LEDs to minimise variability. This is especially important for large projects where consistency is important. Garden Q records the bins of LEDs supplied to individual customers allowing the re-supply of LEDs to match previous installations.

Q: Should LEDs be operated using an AC power supply or a DC power supply?
A: All Garden Q luminaires can be operated using 24 V DC ripple free power supplies. It is important to note that 24 V DC ripple free power supplies are FAR more efficient than 12 V AC and will support more fixtures. High frequency electronic transformers cannot be used and may irreparably damage the on board driver.

Q: Which transformer should I use and how many luminaires can I run off a single transformer or power supply?
A: See the transformer page for transformer capacities.

Q: Are LED luminaires to be wired in series or in parallel?
A: All Garden Q LED luminaires are standard with integral LED drivers drive and must be connected in parallel (the same as conventional luminaires). Some fixtures have the option of using a remote drive must be connected in series.

Q: Are LEDs dimmable? Can a basic residential dimmer be used?
A: Garden Q low voltage drivers have a dimming feature as standard. An additional pair of wires for the dimming signal is required to be run to each luminaire. Dimming is available using 0-10 volt dimming module. A basic residential dimmer cannot be used however Garden Q can provide a wall plate style dimmer to use in conjunction with the dimming module.

Q: Do I need a constant current driver and why?
A: Garden Q offers two options for powering some luminaires: built-in low voltage drivers (integral constant current or remote LED drivers. Generally the simplest thing is to use the Garden Q built in low voltage constant current drive which is supplied as standard and connect to a Garden Q 24 V DC ripple free Power Supply.