The phrase "a lamp that would" is correct and usable in written English.
It can be used when describing a lamp that has a certain quality or function that is conditional or hypothetical.
Example: "I wish I had a lamp that would change colors based on my mood."
Alternatives: "a lamp capable of" or "a lamp designed to".
An example is solar lights, which are designed to break down with parts not found in the country so they have this constant cycle of going into debt to buy a lamp that would break".
He wrote poetry; he had lively friendships with some of the best-known writers of his day; he invented a lamp that would prevent methane gas from exploding and save the lives of countless miners.
While spending a dark winter there as an Army staff sergeant during World War II, Hansen built a lamp that would allow him to read in bed: a length of copper tubing, bolted to the wall, bent and wired with a bulb at the end.
In the late 18th century a demand arose in England for a miner's lamp that would not ignite the gas methane (firedamp), a common hazard of English coal mines.
I devoted as much care to making a lamp as I did to making a sculpture, because I felt that if I could make a lamp that was a really good lamp, that would help me with everything else.
Clanny developed a miner's lamp that would not ignite firedamp but was unwieldy; he later reduced its bulk and adapted several improvements devised by Davy, one of which was a shield of metal gauze.
Then he gradually adjusted his light, first to show the pathetically weak illumination of a coal-oil lamp that would have been used in the early days of the mines, and then to show the only marginally more intense beam of a later-day coal-miner's helmet lamp.
Davy constructed a miner's lamp that would not explode in the presence of methane, much to the delight of British miners and mine owners alike.
Playing around in his kitchen, he stirred together sugar with water and cream of tartar (a similar concoction to that used for the skulls), which he could then mold into products — the most popular being an ethereal-looking lamp that would be at home in an Antoni Gauda building ($500; www.godoylab.com).
Similarly, a lamp that is festooned with cartoon characters would have to be tested, but a lamp without the characters would not.
A lamp that creates light with little or no heat or magnetism would be very efficient.
