Aluminium Reflector Halogen AR56 - GBG
During the 1960s there was a growing trend to apply low voltage lamps in high-end accent and display spotlighting applications. Several manufacturers developed miniature incandescent reflector lamps based on 6V, 12V and 24V filaments - the lower voltage coils having more compact dimensions and higher efficacies than mains voltage types. This greatly facilitated the creation of narrow beam angles of considerably higher luminous intensities than before, and also with a notable improvement in beam uniformity.

Although low voltage halogen capsules had already been used in such applications, and the concept of a halogen capsule with integrated reflector also existed for film projectors, Philips first to develop a low voltage halogen halogen reflector lamps specifically for display spotlighting.

This lamp was introduced around 1978, with several novel design features. Most notable is a shift from glass dichroic reflectors to a simpler design made from spun aluminium sheet. This of course meant that these lamps lacked the cool beam of dichroic mirror lamps, but Philips considered that to be unnecessary for general lighting. A glass front lens was also introduced, not only to facilitate handling and protect the inside from dust and contamination, but for safety in case the inner capsule should shatter. A third novel feature was the first use of a bayonet cap on a low voltage halogen reflector lamp, simplifying installation and replacement. The Philips "AR56" aluminium reflector 56mm lamps were later joined by smaller AR37 versions and remained in production until around 2018-2019. However their popularity began to dwindle from the early 1990s as consumers showed a clear preference for the MR16 dichroic reflector alternatives.
Manufacturer: Philips Lighting
Lamp Power: 35 Watts  
Lamp Voltage: 6 Volts  
Lamp Current: 5.83 Amperes  
Cap Type: B15d Ni plated + Vitrite insulator
Bulb Type: AR-56 AR-17.5 in eighths/inch
Bulb Finish: Clear Glass Aluminium reflector
Filament Type: C-6 Transverse Single Coil
Atmosphere: Bromine, Krypton
Luminous Flux: N/A  
Luminous Efficacy: N/A  
Luminous Intensity: 17,000 cd  
Beam Distribution: 6° to 50% peak
Colour Temperature & CRI: CCT: 3000K CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.452 CCy: 0.409
Lifetime: 2000 hours to 50% survival
Burning Position: Universal  
Overall Length: 56±2 mm 2 3/8"
Light Centre Length: N/A  
Factory: Turnhout Belgium
Date of Manufacture: August 1979 Date Code 9H
Original Value: GB £8.20 (1988)  
References: 1) Philips Catalogue 1978 International Edition
2) Philips Price List 1988 UK
3) Philips Price List 2018 Belgium (last known listing)
4) Philips Price List 2019 Belgium (no longer listed)