The principle of "classical" transformer based on the law of electromagnetic induction. In the primary coil under the influence of an applied alternating voltage a magnetic field producing an alternating magnetic flux in the core, proportional to this voltage, which, in turn, induces EMF in secondary windings. This EMF is directly proportional to the number of turns of the windings.
In electronic transformer (ET) the principle of operation is completely different. Essentially, FL is a switching power supply (voltage Converter) electronic protection against short circuit and overheating of the elements. Ballasts energy saving devices lamps similar in principle of operation.
As shown by my experiments, electronic transformer can be used to of any active power to the load, not exceeding in power options, FL. As a rule, these parameters are indicated on the instrument housing. For example, the output of the FLOOR can be to turn on the heating element, the voltage of 12 V, the current consumption not more than 1.5 A, or automotive incandescent lamp 12 watt (as the light detector).
In pulse mode ET is able to supply power to the load the power of 24 watts (2 of the same type of automotive lamps).
Given the small dimensions and high efficiency, electronic transformer in some cases much easier normal.
Author: A. Kashkarov, St.-Petersburg