I had an electrician install 30, PAR30 LED Bulb - 40 Watt LED Spotlight Bulb/Flood Light Bulb - Natural White 36 Degree. I did the geometry in advance as the lamps
were in 6 rows of 5. There rows varied in height at 22', 24' or 26' . The room was 42' x 72'. This is a multi-purpose room for a church. The new LED's provide great improvement for reading, etc. over the old Par30, 300 watt incandescent lamps. We also used extenders to get the lamps closer to the opening of each can. 2 per can.
There were old wall dimmers for each row(6). The electrician had to replace them with simple off/on wall switch so we did not have any flickering. The new lamps have transformed the room. Coverage is even and light much brighter. Everyone is thrilled with the results.
A discharge lamp has a glass or silica envelope containing two metal electrodes separated by a gas. Gases used include, neon , argon , xenon , sodium , metal halide , and mercury . The core operating principle is much the same as the carbon arc lamp, but the term 'arc lamp' is normally used to refer to carbon arc lamps, with more modern types of gas discharge lamp normally called discharge lamps. With some discharge lamps, very high voltage is used to strike the arc. This requires an electrical circuit called an igniter, which is part of the ballast circuitry. After the arc is struck, the internal resistance of the lamp drops to a low level, and the ballast limits the current to the operating current. Without a ballast, excess current would flow, causing rapid destruction of the lamp.