Energy Efficiency - Bulbs or Globes cont.

LED's
The 1970s saw the use of red, green and yellow LEDs  as electronic indicators. The first HP calculators used a small array of LEDs to indicate the numerals. Previously Nixie tubes and gas plasma displays were used for this purpose.

In 1995, Nichia, a comparatively small company, produced a high brightness blue LED. Previously, a few blue LEDs had been made, but they were very expensive to produce and too dim to be practical as indicator lamps. Further developments followed, with Philips making white light LEDs using a fluorescent material to combine blue light with yellow light from the LED chip to produce a white light. White light LEDs had also been made by combining a red, green and blue die in one envelope, but these were not particularly bright. Nowadays, LEDs seem to operate by using a UV emitting die and fluorescent materials. These were pioneered by Cree in 2003. Cree's latest products are comparable in efficiency with compact fluorescent lamps in terms of lumens per Watt - a measure of luminous efficiency. Torches and handlamps using Cree LEDs are available from Afrishop.

High-Intensity Discharge

HID LampA high-intensity discharge (HID) lamp operates by producing an electric arc between tungsten electrodes in hoHID Hand Lampused inside a fused quartz tube. These lamps became popular in motor vehicle headlights. They are also used to illuminate football stadiums, gymnasiums etc, anywhere where high levels of lighting are required. They are also now available in flashlights and for other portable lighting, where their high efficiency helps to extend battery life. An HID torch is shown at right.

HID lamps are a form of gas-discharge lamp, and like fluorescents, require a ballast. In portable applications and where high efficiency is required, an electronic ballast is used to provide the high voltage required.

The arc from a HID light produces UV radiation, so that most HID lamps are enclosed in an outer UV-resistant envelope.

Fluorescent

Fluorescent lamps became available in the mid 1930s. They consist of a glass tube with heating elements at each end, containing an inert gas at low pressure. The inside of the tube is coated with a fluorescent material.

If a voltage is applied to the heaters, they enit free electrons. If a subsequent high voltage is now applied acroos the tube, there will be a flow of current which will increase until the tube overheats and self-destructs. To prevent this, a ballast is used to limit the current. (In DC circuits a resistor could be used - but it would dissipate as much power as the lamp). Normally, a magnetic ballast is used as a current limiter.

The flow of current in the tube excites the atoms in the inert gas to produce ultra-violet rays. These are converted by the fluorescent coating on the inside of the tube to visible light. (The starter in a fluorescent tube momentarily connects the heaters - once current flow is initiated, there is no futher need to power the heaters externally).Base For CFL

Nowadays, the magnetic ballast is being replaced with an electronic ballast, which is much more energy-efficient. The compact fluorescent lamps now replacing incandescent lamps (by law in many countries) are simply fuorescent lamps with an electronic ballast in the base. These bases are also available separately.

Compact fluorescent lamps (CFLS) are available with lectronic ballasts to operate from 230 volts AC, as well as 12 volts DC. The 12 volt CFLs are suitable for camping and recreational purposes. They may also be used for emergency lighting without the need for a separate inverter.

Fittings

Edison Screw

The Edison screw cap was developed by Edison for his new incandescent lamp. It is said that Edison got the idea for this connector from the cap of a hot-water bottle. This comes in many sizes. The most familiar being the Miniature Edison Screw (MES) used in torch lamps and the 27 mm Edison Screw (ES) used in many mains light fittings. In chandeliers and decorative lights the Small Edison Screw is often used. Large mercury-vapour lamps, street lights etc often use the Giant Edison screw (GES). There is also a Lilliput Edison screw, which you will find in the Mini-Maglite and a “Candelabra Edison Screw” - midway in size between the SES and MES. These are very uncommon in South Africa.

The Edison screw designation is given by the letter E followed by the diameter in mm, as in the following table:



Copyright. ©  Absolute Energy Solutions. All rights reserved.
Designation
Designation Diameter mm
Name
Name Abbreviation
  E5
  5
  Lilliput Edison Screw
  LES
  E10
  10
  Miniature Edison Screw
  MES
  E12
  12
  Candelabra Edison Screw
  CES
  E14
  14
  Small Edison Screw
  SES
  E27
  27
  Edison Screw
  ES
  E40
  40
  Giant Edison Screw
  GES
There are differences in size between the European sizes above and the American sizes - for example the E39 and E26 sizes for ES and GES respectively. The abbreviation MES is sometimes used for "Medium Edison Screw" in North America.

Bayonet Mount
The "Bayonet Mount" connector is the familiar "twist and click" fitting used in the majority of homes for lighting before the advent of down lighters with their twist-lock fitting. The advantage of the bayonet fitting is its ability to withstand vibration or loosening due to temperature variations. The bayonet fitting is also less likely to jam or seize in the base.
Bayonet mounts may have one, two or more pins, and there are many custom sizes for special purposes. Here is a table of common sizes.



Designation
Designation Diameter mm
Name
Name    Abbreviation
  BA5s
  5


  BA7s
  7


  BAX9s
  9


  BA9s
  9
  Miniature Bayonet Cap
  MBC
  BA15d
  15
  Small Bayonet Cap
  SBC
  BAX15s
  15


  BA15s
  15
  Single Centre Contact
  SSC
  BA20s
  20


  BA20d
  20


  BA21d
  21


  B21-4
  21 (4-pin)


  BA22d
  22
  Bayonet Cap (Familiar domestic fitting)
  BC
  BC-3
  22 (3-pin)


  B22d
  22
  Double ended

  BX22d
  22


The suffix d means 2 centre contacts, s means a single contact.

Bipin (Bi-Pin)
This fitting is used principally for halogen lamps and the ends of Fluorescent lamps. This base was invented by Reginald Fessenden for the 1893 World's Fair in Chicago. Edison's arch rival Westinghouse was given the contract for this and Edison refused to allow his patented Edison screw bulbs to be used.



Designation
Standard
Pin Center to Center mm
Pin Dia mm
Use
  G4
  IEC 60061-1 (7004 -72)
  4
  0.65-0.75
  MR11 and other small halogens
  GU4
  IEC 60061-1 (7004-108)
  4
  0.95-1.05

  GY4
  IEC 60061-1 (7004-72A)
  4
  0.65-0.75

  G5
  IEC 60061-1 (7004-52.5)
  5

  T6 and T5 Fluorescent
  G5.3
  IEC 60061-1 (7004-73)
  5.33
  1.47-1.65

  G5.3-4.8
  IEC 60061-1 (7004-126-1)



  GU5.3
  IEC 60061-1 (7004-109)
  5.33
  1.45-1.6

  GX5.3
  IEC 60061-1 (7004-73A)
  5.33
  1.45-1.6
  MR16 and other small halogens
  GY5.3
  IEC 60061-1 (7004-73B)
  5.33


  G6.35
  IEC 60061-1 (7004-59)
  6.35
  0.95-1.05

  GX6.35
  IEC 60061-1 (7004-59)
  6.35
  0.95-1.05

  GY6.35
  IEC 60061-1 (7004-59)
  6.35
  1.2-1.3

  GZ6.35
  IEC 60061-1 (7004-59A)
  6.35
  0.95-1.05

  G9
  IEC 60061-1 (7004-129)
  9


  GU10

  10

  Twist-lock MR16 Halogen lighting
  G13

  12.7

  T8 and T12 Fluorescent
  G23

  23
  2

  GU24

  24

  Twist-lock for CFL
  GX53

  53

  shaped CFL
Fluorescent Fittings

The suffix after the G indicates pin centre-to centre spacing, and a U suffix indicates the pins have two diameters to lock the lamp into place.

Compact Fluorescent
Compact fluorescent lamps without electronic ballast use push-fit rectangular or square fittings.

Conclusion
Lamps not covered yet include mercury-vapour and the various types of lamps used for street lighting. If you have any questions regarding lamps and fittings, please contact us for assistance. Please see our contacts page.