A transformer is a static device that transfers electrical energy from one circuit to another through inductively coupled conductors-the transformer’s coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer’s core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF) or “voltage” in the secondary winding. This effect is called mutual induction. Source: http://en.wikipedia.org/wiki/Transformer
Electronic transformers are usually more efficient than magnetic transformers. They are also much smaller in size and weigh far less than an equivalent magnetic transformer.
Most LED products (LED strips mostly) can use electronic transformers (or electronic drivers) to function. However, many electronic transformers (especially LED electronic transformers) are not dimmable and may not be a good fit for homes or location where the ability to dim lights is a requirement.
On the other hand, electronic transformers are ideal for LED RGB strip systems because the frequency that magnetic transformers function on can cause a harmonic distortion which results in flickering, oscillating or just failing systems. The majority of LED RGB strip systems using electronic transformers can be dimmed using the LED RGB controller which “controls” the system.
There are several electronic transformers (also referred to as electronic drivers) to choose from but most LED applications require a DC electronic transformer (Direct Current).