Continental Refrigeration 40070

BALLAST F40 LAMP MED. 1&2 SEC

An electrical ballast is a device that limits the current through an electrical load. These are most often used when a load (such as an arc discharge) has its terminal voltage decline when current through the load increases. If such a device were connected to a constant-voltage power supply, it would draw an increasing amount of current until it is destroyed or causes the power supply to fail. To prevent this, a ballast provides a positive resistance or reactance that limits the current. The ballast provides for the proper operation of the negative-resistance device by limiting current. Series resistors are used as ballasts to control the current through LEDs.

A replaceable component that produces light from electricity is called a lamp or a bulb. Lamps are commonly called "light bulbs". A wide variety of lamps/bulbs are used in restaurant equipment from refrigerators to merchandisers, and ovens to orbital mixers. Lamps usually have a base made of ceramic, metal, glass, or plastic, which secures the lamp in the socket of a light fixture. The electrical connection to the socket may be made with a screw-thread base, two metal pins that fit into a receiving clamp, two metal caps or a bayonet cap. The three main categories of electric lights are:

• Incandescent lamps, which produce light by a filament heated white-hot by electric current
• Gas-discharge lamps, which produce light by means of an electric arc through a gas
• LED lamps, which produce light by a flow of electrons across a band gap in a semiconductor.

A "sensing bulb" is the temperature sensing device (probe) of a thermometer, RTD, or thermistor. The 'bulb' refers to its shape and has nothing to do with lighting.