Tungsram FD*7W 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.

Several of the Eastern European lampmakers were fast to adopt the new technology, but production remained on a small scale until the opening of their markets. Most introduced direct copies of the Philips or Osram designs, but Tungsram of Hungary developed the type featured on this page, offering an excellent compromise between low manufacturing costs and high performnace.

One of the drawbacks of the U-bent designs of the Osram and Sylvania lamps was the lack of an effective cool spot in the corners of the bends. Tungsram intelligently solved this by blowing the bend into a double-dimpled shape resembling the Philips pi-structure. The extremities of these dimples are positioned far enough from the discharge to run significantly cooler, thereby lowering the mercury vapour pressure and raising performance especially in compact high-temperature luminaires.

It is not certain when this design was introduced, but it is depicted in a 1986 Tungsram patent and of course featured in this 1989 lamp. It appears that Tungsram initially had limited production capacity, because many early lamps of that company are in fact made by other factories - but following its 1990 takeover by GE of America, that company was swift to invest in CFL manufacturing and many of the GE lamps adopted the superior Tungsram bend design.
Manufacturer: Tungsram
Lamp Power: 7 Watts
Lamp Current: 0.175 Amps
Lamp Voltage: 45 Volts
Cap Type: G23 Aluminium + PBT
Bulb Type: T-12.4 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: 400 lm @ 100h
Luminous Efficacy: 57 lm/W @ 100h
Colour Temperature & CRI: CCT: 2700K CRI: Ra 81
Chromaticity Co-ordinates: CCx: 0.460 CCy: 0.414
Lifetime: 5000 hours
Warm-up & Re-strike Time: 2 minutes Instant
Burning Position: Universal
Overall Length: 135 mm 53/8 inches
Lighted Area: 100 x 27 x 12 mm 4 x 11/16 x 1/2 inches
Factory: Nagykanizsa Hungary
Date of Manufacture: 1989 Q2 Date Code: 9 .:
Original Value:
References: 1) Tungsram Catalogue c.1988 UK p.21
2) Tungsram New Products for Hanover Fair, 1990 Germany p.16
3) US Patent 4,925422 - Exhaust Head for CFL Lamps - J.Tokes, L.Ugrosdy (Tungsram) - Filed 25-Oct-1988.