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Following the introduction of the Sylvania Capsylite MB-19 lamps in 1986, GE followed in 1987 with this Halogen Performance-Plus TB-19 range. A pair of 51W and 90W lamps were positioned as high performance retrofits for 60W and 100W incandescent lamps, with life increased from 750h to 2000h. The energy saving and life do not match the same high levels as the Sylvania originals, but the GE lamps still achieved great popularity because of their diode-free design that improved compatibility with dimmer switches.
At the heart of the lamp is a small single ended tungsten halogen capsule which contains an unsupported coiled-coil axial filament. In common with other American halogen lamps, the capsule is fabricated in aluminosilicate hardglass instead of the internationally-preferred quartz. This choice of capsule material brings to a minimum the increase in cost vs inacandescent lamps since hardglass is a cheaper material, and the production machinery can also run at much higher speeds and with greater efficiency than for quartz.
Hardglass capsules do however have an elevated risk of shattering at end of lamp life. To avoid risk of damage or injury, the outer bulb is blown in heavy-wall glass designed to withstand the force of a capsule explosion. It is also coated externally with a protective Teflon coating, designed to hold the fragments together in case it should be broken. The bulb is acid-etched on its outer surface to provide a diffusing effect. The capsule is ingeniously welded to a metal support frame which engages in grooves moulded into the bulb neck, and the ends of this frame are firmly clamped in place by screwing the brass cap over the threaded end of the glass bulb, without need for cement. |