In this topic, you study Compact Fluorescent Lamp – Working Principle, Construction & Circuit Diagram.
Construction of Compact Fluorescent Lamp
Basically compact fluorescent lamp (Fig. 1) is a type of fluorescent lamp. There are two types of these lamps :
- Integrated type,
- Non-integrated type.
Fig. 1: A typical compact fluorescent lamp (C.F.L.)
Integrated type
Integrated type lamps have a compact arc tube, an electronic ballast (choke) and either a screw or bayonet type fitting combined in a single unit. With such a construction, these lamps work well in standard incandescent fixtures and therefore can easily replace incandescent lamps.
Non-integrated type
In non-integrated type, compact fluorescent lamp does not include a ballast in itself. Therefore, such lamps allow low cost replacement of consumable tubes and the extended use of electrical ballasts in a light fixture. Non-integrated compact fluorescent lamp housings are both more expensive and sophisticated, providing options such as dimming, less flicker, faster starts, etc.
Operation of Compact Fluorescent Lamp
Compact arc tube of a lamp contains a high-pressure mixture of argon and mercury. Like ordinary fluorescent tubes, in this case also, the light is produced by passing an electric arc through a mixture Of these gases. The ballast used provides proper starting and operating voltages and regulate the current flow in the lamp. Increasing use of electronic ballasts has removed most of the flickering and slow starting traditionally associated with fluorescent lighting. Compact fluorescent lamps generally radiate a different light spectrum from that of incandescent lamps. However, now-a-days with the improved phosphor formulations, the lamps emitting soft white light similar in colour to standard incandescent lamps are also available.
Applications of Compact Fluorescent Lamp
- Compact fluorescent lamps produced for both alternating current and direct current. Integrated type compact fluorescent lamps are finding increasing use in domestic applications. D.C. compact fluorescent lamps are popular for use in recreational vehicles and off-the-grid housing. D.C. fluorescent lamps operating on car batteries, solar panels and small wind generators are increasingly used in rural parts to replace kerosene lanterns.
- Non-integrated compact fluorescent lamps with external ballasts having dimming capabilities are more popular for professional users, such as hotels and office buildings.
Advantages of Compact Fluorescent Lamp
- Modern compact fluorescent lamps generally have a lifespan of between 6000 to 15000 hours as against 750 to 1000 hours for incandescent lamps.
- For a given light output, compact fluorescent lamps use between 20 to 25
Disadvantages of Compact Fluorescent Lamp
- Purchase cost of a compact fluorescent lamp is nearly 3 to 10 times greater than that of an equivalent incandescent lamp. However, extended lifespan and lower energy use compensate for the higher initial cost in many applications.
- Compact fluorescent lamps can fail prematurely if overheated.