The incandescent light bulb is the traditional electric lighting mode. It produces light by heating a filament wire to a high temperature until it glows. The hot filament is protected from oxidation in the air with a glass enclosure that is filled with inert gas.
Compact fluorescent lamp (CFL)
A CFL is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light producing visible light. A fluorescent lamp converts electrical power into useful light more efficiently than an incandescent lamp. CFLs have two main components: a gas-filled tube (also called bulb or burner) and magnetic or electronic ballast.
Light-emitting diode (LED)
An LED is a semiconductor light source. When the LED is switched on, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons as visible light. LEDs present many advantages over incandescent light sources and CFLs including lower energy consumption, longer lifetime, improved robustness, smaller size, and faster switching.
Compare the light output and efficiency of incandescent lamps, CFL and different kinds of LED lamps: The colour temperature of the electromagnetic radiation is defined as its surface temperature in Kelvin. For example, a warmer (i.e., lower color temperature) light is often used in public areas to promote relaxation, while a cooler (higher color temperature) light is used to enhance concentration in offices.
To fix the lamps there are different sockets. Find the right lamp or lighting unit for your lighting purpose. Lamps are usually inserted in sockets which provide electrical connections to the bulb and support it in the lighting fixture. The use of sockets allows lamps to be safely and conveniently changed out at the end of life. Some lamps have wire leads suitable for direct connection to wires others have screw terminals for wire connections. (You find those in the chapter lighting units.)
There are many different standards of sockets, here are the most important ones for PV systems.
E14: This is a small screw in socket with a base diameter of 14 mm, known as Small Edison Screw (SES).
E15: The E15 is a standard for small light bulbs in many Asian countries. For their lighting products Sundaya established this socket as Sundaya Standard.
E17: E17 is a screw in socket with a base diameter of 17 mm, known as Intermediate Edison Screw (IES).
E27: This is the standard incandescent socket base that we are all very familiar with. Most bulb shapes are available with this base.
G4: G4 plug-in bases (4 mm distance between the metal pins) are perfectly suitable for builtin spots and mobile homes.
G13: G13 is a standard for CFL and LED tubes.
GU5.3: These sockets have two parallel pins. Distance between the pins is 5,3 mm. GU5.3 is a small version to be connected easily. This base has two pins that „push“ in the socket. It is most commonly found in pot lamps, track lighting, and other small fixtures.
GU10: This base has two prongs that „twist“ in the socket. Distance between the pins is 10 mm. It is most commonly found in pot lights or many ceiling or table lamps.
Bayonet: The bayonet light bulb mount is the standard fitting in many former members of the British Empire. The standard size is B22d-2, often referred to in the context of lighting as simply BC. Older installations in some other countries, including France use this base. Standard bulbs have two pins on opposite sides of the cap.
Apollo Bayonet: The manufacturer Sundaya developed an easy to use Plugand Play Technology for their PicoPV product ranges Ulitium and T-lite. The products are based on the Apollo Bayonet.