Articles Related to: Transformer
How To Fit Kitchen Down Lights
The thing is that all LED light bulbs are inherently low voltage; it's just that the "mains" powered ones are designed with an integral LED driver (transformer), thereby saving you the trouble of figuring out the correct type of transformer for LED light bulbs. Not that you cannot opt for separate 12v transformer(s) and low voltage LED lights if you want to (for some situations, boats and caravans being obvious examples, you only have access to 12 volts anyway). It's just an extra complication ... Can You Mix ‘n Match Transformers With LED Lights?
So you've bought some low voltage LED lights, or lost the Transformer that drives your LED Christmas lights and you're wondering whether you can just reuse some random 12 volt Transformer you just happen to have kicking around.
Well the short answer is: probably not (unless you got really, really lucky). Just because whatever Transformer you happen to have in your hand converts from say 230 volts to 12 volts does not mean it is suitable for driving whatever 12 volt application you had in mind (your LED lights in this case).
Take a look at a few Transformers ... Still Using Halogen Lamps? Are You Mad?
On the subject of 12v lighting, you *can* replace existing 12v MR16 halogen lamps with LED versions but you will almost certainly have to additionally replace your low voltage transformers with LED drivers (basically better quality constant voltage, low load transformers) to avoid frying your new bulbs. You will also discover that the qualitative differences between mains and low voltage that exist with incandescent bulbs don't apply to LEDs, so a better option for many ... What To Look For When Buying LED Spotlights
To replace mains powered halogen spot lamps you need to be looking at LED GU10 format lamps, whereas for low voltage systems you want MR16 LED spot lights (and you will also have to replace the existing step-down transformers with much more precise versions called LED drivers).
In fact, you may want to consider replacing existing low voltage lighting with mains powered GU10 LED bulbs since (unlike incandescent lighting where the higher current on low voltage systems creates brighter light) there is very little visible difference between mains powered and 12v LED lights. The ... Solar Garden Lighting
People sometimes think that you can simply extend the cable for a conventional low voltage lighting circuit and thus reach into the furthest corners of the garden but in practice there is a maximum length to any cable run. This is often stated on the transformer (or the box containing the cable) and as you add more spurs to feed individual light fittings, this maximum length reduces. Basically the cable itself applies a load to the transformer and there comes a point where so much power is being dissipated by the cable ... 
