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MR16 & GU10 bulb and socket types

The MR16 (GU5.3) and GU10 bulbs are commonly seen in residential and commercial downlight and spot light applications. Retail lighting applications tend to use narrower beam angles of less than 45° to create accent lighting or highlighting of products. These types of bulbs are also sometimes referred to as PAR16 or PAR20 bulbs due to their relatively narrow diameter, although the latter typically come in the Edison style screw socket.


Most modern residential homes in Australia will utilise either a 12V 50W MR16 or 240V GU10 50W dichroic halogen light bulbs in their ceiling downlights. Our LED MR16 and GU10 bulbs are an ideal replacement with an electricity saving of between 75% to 90% depending on the configuration and a reduction in heat generation of up to 80%. That means as little as one tenth of the usual electricity bill for running your lights and up to 30% saving on your air conditioning electricity usage due to the reduction in heat.

MR16 and GU10 light bulbs are identifiable by their different sockets as shown in the diagram. The key difference being that the MR16 light bulb requires a low voltage 12V electronic transformer and the GU10 simply plugs into a mains power 240V AC socket and does not require an additional transformer. Whilst both socket types are relatively safe, one cannot be electrocuted with the 12V MR16 light globe socket whereas with the GU10 sticking a metal object into the small cavities of the socket could result in electrocution, although this would be very unlikely.

Both MR16 and GU10 light bulbs come with the same LED chip design which may incorporate an older independent multi LED format (see figure below) or a newer combined multi LED format or a chip on board (COB) type. These days in more compact light designs it is rare to see the independent multi LED format, although some of these are still produced due to cost savings or simply the use of older technology which suits some smaller LED types.

The push for a single LED source or COB LED has been aimed at replicating a small source or point source to create a single shadow with a crisp outline, unlike the multi-LED sources or first generation MR16 LEDs which create a fuzzier outline through the prescen of multiple sources, typically 4 or 5 LEDs. In most applications neither is a disadvantage, although the single point source more closely replicates the traditional dichroic halogen.  


The MR16 LED light bulbs are compatible with most 50W electronic halogen 12VAC downlight transformers. You can check our list attached to each MR16 LED light bulb type or mail your electronic transformer to us and we will test it for you. As discussed in the section on “LED light bulb – Driver and Power Supplies” you can replace your halogen downlight transformer by purchasing a constant voltage 12V DC LED transformer or driver to save further electricity and extend the life of your LED lighting system. The latter we specifically recommend for commercial applications or those applications where the LED light bulb is exposed to extended operating hours or extreme temperatures. Otherwise the GU10 LED light bulb type is fine for most residential applications and usually the most economical choice.

Also if you wish to replace your old 50W halogen downlight transformers by law you will require a licensed electrician unless the transformers have a plug in mains socket in the ceiling space, which in such cases you can simply unplug the light and purchase your LED driver with a mains plug already attached.

Otherwise the MR16 LED bulb is simply a push in fit, whereas the GU10 bulb is a push in and twist fit much like a standard B22 light bulb. As most people would know a licensed electrician is not required to change a light bulb, only if there is mains wiring to be performed. 

The only other issue to remember is whether or not your existing downlight fitting is restricted in terms of space. Some MR16 and GU10 LED light bulbs have a relatively longer length to increase the size of the heat sink and will not fit in some downlight fixtures. In such cases you can choose a shorter MR16/GU10 LED light bulb or purchase your MR16/GU10 LED light bulb with one of our compatible fixtures. 

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