Types of light bulbs

By

Terry Rawkins

Copyright © 2020

terryrawkins@gmx.co.uk

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Table of Content

1. Light Bulbs

2. Physical outline

3. Base or Cap type

4. Lighting technology

5. Reference material

Light Bulbs

The familiar light bulb has been with us for over 100 years and is now changing both it's looks and the technology that make it work.

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1 Physical outline

The traditional light bulb type is known as the A-series light bulb. For example an A60 bulb which is 60 mm wide at its widest point and approximately 110 mm in length.

2 Base or Cap type

The base, the part that you fit into the light fitting is changing, it's now smaller and easier to produce than the old type.

The original A-series light bulbs in the UK would have been of the older bayonet twist type base known as BC for bayonet cap or sometimes B22. There is also a small bayonet SBC or B15

Bayonet Cap

Edison Screw

Some A60 light bulbs in the UK have an E27 type base. The E27 or Edison Screw ES indicates a screw connection of size 27 mm

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Small Edison Screw

A smaller size base is also available, the E14 or Small Edison Screw SES which has a 14 mm threaded base.

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GU10 Base

Popular spotlight fittings typically use a GU10 turn-and-lock base.

So they cannot be accidentally interchanged with low-voltage lamps the GU10 is distinguished from the lower-voltage MR lamps by the U-shaped ceramic base.

The GU10 is a 2-pin bayonet like base with 10 mm distance between pins.

Lamps with a GU10 base can be used anywhere in the home, from the bathroom to workspaces where you want a little extra focus. As with the older, less efficient Halogen GU10, the LED GU10 features two pins at the base, which means in most cases they can be retrofitted into existing halogen fixtures.

There are adaptors / converters that enable you to use a GU10 bulb in a BC or ES light fitting.

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3 Lighting technology

The modern incandescent light bulb, with a coiled filament of tungsten, was first patented in 1906, it had been developed from the carbon filament lamp introduced in C 1880.

Less than 3% of the input energy is converted into usable light. Incandescent bulbs are being phased out in many countries due to their low energy efficiency.

Halogen lamps

Halogen lamps, which are usually much smaller and operate at a higher temperature than a standard incandescent lamp of similar power and operating life are used in certain applications. Halogen lamps produces light with higher luminous efficacy and colour temperature.

Halogen lamps should not be touched with bare hands, oily fingerprints can create local hotspots which can damage the glass bulb.

LED

An LED lamp or LED light bulb is an electric light for use in light fixtures that produces light using one or more Light Emitting Diodes. LED lamps have a lifespan many times longer (15 times) than equivalent incandescent lamps, and are significantly more efficient than most fluorescent lamps.

Similar to incandescent lamps (and unlike most fluorescent lamps), LEDs come to full brightness immediately with no warm-up delay.

Frequent switching on and off does not reduce life expectancy. Light output decreases gradually over the lifetime of the LED

Of the three types of lamp mentioned here the LED lamps are perhaps 6 times more efficient than the old incandescent bulbs. Because of this the older types are now being phased out in many jurisdictions .

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Reference material

https://en.wikipedia.org/wiki/A-series_light_bulb

https://en.wikipedia.org/wiki/Edison_screw#Types

https://en.wikipedia.org/wiki/Bi-pin_lamp_base

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28 December 2020

Table of Contents

Light Bulbs

Physical outline

Base or Cap type

Lighting technology

Reference material