Electrical Engineers have been trying to budge "Old Yellow," the low-pressure sodium vapor lamp, from the top of the efficiency heap since the mid-1960s. They found some materials possibilities in the 1990s, but all have turned out to be too expensive.
Fun Fact:
Electrical Engineers have been trying to budge "Old Yellow," the low-pressure sodium vapor lamp, from the top of the efficiency heap since the mid-1960s. They found some materials possibilities in the 1990s, but all have turned out to be too expensive.