produces an initial high voltage on the coil to start a gas discharge; thereafter the voltage is reduced to normal running level. The system can be seen as a type of transformer, with the power coupler (inductor) forming the primary coil and the gas discharge arc in the bulb forming the one-turn secondary coil and the load of the transformer. The driver is connected to mains electricity, and is generally designed to operate on voltages between 100 and 277 VAC at a frequency of 50 or 60 Hz, or on a voltage between 100 and 400 VDC for battery-fed emergency light systems. Many drivers are available in low voltage models so can also be connected to DC voltage sources like batteries for emergency lighting purposes or for use with renewable energy (solar and wind) powered systems. In other conventional gas discharge lamps, the electrodes are the part with the shortest life, limiting lamp lifespan severely. Since an induction lamp has no electrodes, it can have a longer service life. For induction lamp systems with a separate driver, the service life can be as long as 100,000 hours, which is 11.4 years of continuous operation. For induction lamps with integrated drivers, the lifespan is in the 15,000 to 50,000 hours range. Extremely high-quality electronic circuits are needed for the driver to attain such a long service life. Such lamps are typically used in commercial or industrial applications. Typically operations and maintenance costs are significantly lower with induction lighting systems due to their industry average 100,000 hour life cycle and five to ten year warranty. Advantages Long lifespan due to the lack of electrodes – strictly speaking, almost indefinite on the lamp but between 25,000 and 100,000 hours, depending on lamp model and quality of electronics used; High energy conversion efficiency of between 62 and 90 lumens/watt (higher power lamps are more energy efficient); Disadvantages Some internal inductor lamps that use high-frequency drivers can produce radio frequency interference (RFI) that can interfere with radio communications. Newer external-inductor type lamps use low-frequency drivers that usually have FCC or other certification, thus suggesting compliance with RFI regulations. Some types of induction lamps contain mercury, which is highly toxic if released to the environment. See also List of light sources Induction cooker References External links Electrodeless Induction Lamps, Museum of Electric Lamp Technology Gas discharge lamps