Context: Track lighting, invented by Lightolier, was popular at one period of time because it was much easier to install than recessed lighting, and individual fixtures are decorative and can be easily aimed at a wall. It has regained some popularity recently in low-voltage tracks, which often look nothing like their predecessors because they do not have the safety issues that line-voltage systems have, and are therefore less bulky and more ornamental in themselves. A master transformer feeds all of the fixtures on the track or rod with 12 or 24 volts, instead of each light fixture having its own line-to-low voltage transformer. There are traditional spots and floods, as well as other small hanging fixtures. A modified version of this is cable lighting, where lights are hung from or clipped to bare metal cables under tension.

Question: Who invented track lighting?
Answer: Lightolier

Question: What feeds all the fixtures in low voltage tracks instead of each light having a line-to-low voltage transformer.
Answer: master transformer

Question: What  type of lighting uses lights that are hung or clipped to bare metal cables?
Answer: cable lighting

Question: How many volts does a track lighting system usually use?
Answer: 12 or 24 volts