12V transformers

A LED or halogen lamp transformer?
When you are planning to replace your halogen spots with LED spots then you will need to stop and think about the various 12V transformers that you can and cannot use for 12V LEDs.

We make a distinction between 3 types of 12V transformers:

1. Wound transformers
LEDs can be powered with traditional wound or magnetic core transformers, although these transformers do need a minimum load to work properly. A transformer may, for example, need to be connected to lamps with a total load of at least 20W (depending on the type of transformer).

Moreover, wound transformers often have a secondary voltage that is not exactly 12V but which is, for example 13V or 14V. Too-high voltages are extremely harmful for LEDs, as they will become much too hot. You can recognise these transformers immediately from their weight: they are relatively heavy. The disadvantages of these transformers are their possible hum and the high standby power consumption. Wound transformers can be recognised from the following symbol:

2. Electronic transformers
Electronic transformers are much lighter than wound transformers. They are not usually suitable for LED lighting as their load will be too low for the transformer. When you exchange halogen lighting for LEDs you will not usually be able to reach the transformer’s minimum load. The minimum load is shown on your transformer’s label. Electronic transformers can be recognised from the following symbol:

3. LED transformers
These are also known as stabilised transformers. Obviously, these transformers are ideal for LED lighting. Moreover, they do not have a minimum load. Furthermore, and at least equally important, the standby power consumption is very low.

Conclusions

Wound transformers can be used, provided that the secondary voltage is exactly 12V. Electronic transformers will not usually be suitable for LEDs.
We recommend that you use a transformer designed for LEDs, as you will then get the maximum out of your LED lighting.