Sylvania F5TT/27K Compact Fluorescent
Following the launch of Philips' PL* compact fluorescents in 1981, it immediately became clear that this would set an important new global light source standard. By late 1983 Osram had caught up with its Dulux S equivalent, and GTE Sylvania was third to market in 1984.

Sylvania began its compact fluorescent activities in the USA, and established pilot production at its Montoursville PA photoflash plant. However, it quickly became apparent that the global centre of gravity in such lamps was emerging in Europe - where higher electricity costs fuelled the early adoption of these energy-saving light sources. As such, development was taken forward by the company's European fluorescent centre at Erlangen in Germany, with production being established at the Charlestown plant in England.

Whereas Osram introduced several technical variations in an effort to reduce the cost of these lamps, the Sylvania versions have an appearance almost identical to the Osram equivalents. As such they feature a simple U-bent glass tube with squared corners, and a greatly simplified bead-mount type electrode assembly. However, the X-Ray shadowgraph reveals an important technological development. It was found with the Osram design that performance was slightly compromised at high ambient temperatures in compact luminaires, due to the reduced effectiveness of its cold spot around the bend vs the Philips designs. Sylvania introduced an improvement by producing the first amalgam compact fluorescent pin-ended lamps, the spherical pellet being visible inside the exhaustion tip within the lamp cap. Also visible is the highly-reliable Sylvania glowbottle capsule incorporating a getter for superior reliability.
Manufacturer: GTE Sylvania
Lamp Power: 5 Watts
Lamp Current: 0.180 Amps
Lamp Voltage: 35 Volts
Cap Type: G23 Aluminium + PBT
Bulb Type: T-12.5 T-4 in eighths/inch
Bulb Finish: Y2O3:Eu3+, CeMgAl11O19:Tb3+ Soda-lime glass
Electrodes: Triple Coil Tungsten Triple carbonate emitter
Atmosphere: Argon + Hg
Luminous Flux: 250 lm @ 100h
Luminous Efficacy: 50 lm/W @ 100h
Colour Temperature & CRI: CCT: 2700K CRI: Ra 85
Chromaticity Co-ordinates: CCx: 0.464 CCy: 0.411
Lifetime: 5000 hours
Warm-up & Re-strike Time: 2 minutes Instant
Burning Position: Universal
Overall Length: 105 mm 41/8 inches
Lighted Area: 85 x 27 x 12 mm 33/8 x 11/16 x 1/2 inches
Mass:
Factory: Charlestown England
Date of Manufacture: 1987 October Date Code: 22
Original Value: GB £3.15 (1988)
References: 1) GTE Sylvania Lamp Catalogue 1986 UK p.FL-2
2) GTE Sylvania Lamp Catalogue 1984 USA p.74
3) GTE Sylvania Price List 1988 p.41