All 12-volt lighting systems require transformers to convert the mains voltage (usually 230 volts) to 12 volt.
In the past, halogen lighting gained a bad reputation for reliability because poor quality transformers let it down. Good transformers PROPERLY INSTALLED will last and last and provide trouble-free use. Incidentally, 12 volt lighting systems are much more efficient than mains halogen sytems in terms of their light output and, correspondingly, their heat output.
Types of 12 volt sytems include track lighting, recessed downlighting, individual point lighting, garden lighting of different types and IP-rated bathroom lighting.
To control your lighting scheme you will need some controls. This may be nothing more than a simple switch. This will obviously give you full off and full on only. If you want more control to help you create moods, then the simplest way is with a dimmer switch. If using transformers, rather than mains, this must be of the correct type for the transformer you are dimming. We can advise on this aspect for the transformers we sell.
If your 12 volt lighting is divided into more than one circuit, you will need more transformers and more dimmers. This will give you more flexiblity in the use of the lighting. For example, if you have a kitchen/diner with a circuit at either end you can dim one end and have the other brighter, etc.
There are some very complex lighting controls on the market these days which allow you to set moods througout the house and within individual rooms. They are often computer-driven, digital systems. But think very carefully before you commit to this level of control and consider if you really need this degree of complexity. Our experience is that most people who have these systems do not use them freqently and experience high maintenance and re-programming costs.
LEDs require a different type of transformer and controls, usually called a driver. As LEDs vary enormously in their design, it is essential to choose the correct driver for the system. In fact, some LEDs appear not to need drivers at all, this is because they have a built in driver or have been designed in such a way as to run in fittings driven by ordinary 12 volt transformers. (Phillips have recently introduced a range of 7 and 10 watt LEDs which will do this.)
To further complicate the issue most LEDs and their drivers are not dimmable or suitable to go onto systems which have a dimming capability. We can advise on the LED systems we sell as to which driver and which controls need to be used.