ballast

(redirected from ballasts)
Also found in: Dictionary, Thesaurus, Financial, Encyclopedia.

ballast

(bal'ăst),
1. Material of doubtful value itself used to stabilize something (for example, maritime practice). 2. Something largely without intrinsic value.

ballast 

Additional weight of material incorporated in a part of a contact lens to maintain it in a given orientation (Fig. B1). This is often provided by giving prismatic power to the lens (prism ballast lens).
Fig. B1 Truncated and prism-ballasted toric contact lensenlarge picture
Fig. B1 Truncated and prism-ballasted toric contact lens
References in periodicals archive ?
Magnetic fluorescent ballasts market estimate and forecast, 2010 -- 2018 (USD Million)
[ClickPress, Thu Feb 28 2019] Market Research Reports Search Engine (MRRSE) has recently updated its massive report catalogue by adding a fresh study titled " Energy Efficient Lamps and Ballasts Market Valuable Growth Prospects and Insights on Future Scenario -- By MRRSE ".
DOE Energy Conservation Standards for Fluorescent Lamp Ballasts sets forth a regulation that creates a new metric for measuring ballast efficiency and establishes a higher standard of efficiency that will impact many of today's fluorescent T8, T5 and T12 ballasts.
Because people can be exposed to PCBs by breathing contaminated air or by touching materials, leaking ballasts must be removed and properly disposed of along with any part of the fixture that has come in contact with PCBs.
International Resource News-February 21, 2013--State Systems selects Green Ballast's daylight harvesting fluorescent light ballasts(C)1994-2013 ENPublishing - http://www.enpublishing.co.uk
The investigation also revealed another significant problem--the casing around many of the toxic ballasts had broken, allowing PCBs to spread to the fixture housing, wires and diffusers.
One of the issues around the application of CDM lamps on QMH ballasts has to due with the difference in lamp power factor (PF) between these two types.
Environmental Warning: Old ballasts may contain polychlorinated biphenyls (PCBs), a toxic substance that must be disposed of properly.
As fewer UV lamps are required, the number of electronic ballasts is fewer and there is always one for each lamp.
International Rectifier, IR, (NYSE:IRF), El Secundo, Calif., has introduced a single-chip fluorescent lamp ballast device with an active, critical conduction mode, boost-type power factor correction (PFC) method.
* Lighting specialists Ronfell Group, has launched a revolutionary range of 'Multi-Watt High Frequency Fluorescent and Metal Halide Ballast' for the lighting industry.
Against this background, the paper discusses the engineering and economic characteristics of standard and energy-efficient magnetic ballasts for fluorescent lighting.