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Sylvania Mite-T-Light Microminiature B8810 |
Tiny incandescent lamps had existed previously, such as the famous 'Pinlites' of the Kay Electric Company. However, their production required precision manual labour which resulted in high costs and wide quality variations. Sylvania was first to mechanise the production, achieving huge cost reductions and quality improvements. An early application was via Sylvania's own Defence Electronics division for long-range guided missiles. Other applications included photoelectric logic systems for computers, high speed punchcard and tape readers, miniature matrix displays - and even in jewelry and decorative arts. Their primary requirement though, was that their voltage and current were low enough to be illuminated by the tiny currents controlled by electronic transistors.
Both double-ended and single-ended lamps were produced. Thei filament of this example consists of a hairpin-shaped fine tungsten wire, directly welded to a pair of dumet wires. A tiny glass tube is pinched around the wires, constricted above the filament, exhausted to vacuum and sealed via the upper glass tip. Whereas previous lamps required expensive platinum wire seals to avoid glass stresses, Sylvania's cost leadership resulted from its development of extremely fine dumet wires. Despite the initial success, such lamps were quickly superseded by LEDs in the late 1960s / early 1970s, which could operate at still lower currents.
| Manufacturer: | Sylvania Electric Products | |
| Lamp Power: | 0.1 Watts | |
| Lamp Voltage: | 1.0 Volts | |
| Lamp Current: | 0.100 Amperes | |
| Cap Type: | Dumet Wires | 0.127mm x 1.8mm centres |
| Bulb Type: | T-1.4mm | T-0.4 in eighths/inch (0.055") |
| Bulb Finish: | Clear | Soda-lime glass |
| Filament Type: | S-2 | Hairpin |
| Atmosphere: | Vacuum | |
| Luminous Flux: | Approx. 150 millilumens | |
| Luminous Efficacy: | Approx. 1.5 lm/W | |
| Colour Temperature: | Approx. 1950K | |
| Colour Rendering: | Ra 100 | |
| Chromaticity Co-ordinates: | CCx: 0.530 | CCy: 0.408 |
| Lifetime: | Unknown | |
| Warm-up & Re-strike Time: | Instant | Instant |
| Burning Position: | Universal | |
| Overall Length: | 4.4mm | 0.175 inches |
| Light Centre Length | 4.3mm | 0.175 inches |
| Factory: | Boston Street, Salem | U.S.A. |
| Date of Manufacture: | Approx. 1959-1970 | |
| Original Value: | ||
