Electronic transformers and low voltage LEDs?

The electronic transformer is a favourite for 12 volt low voltage halogen lighting. Its small size and efficient operation make it a favourite. As the emphasis is changing to LED lighting there is a lot of confusion on exactly where you stand if you're using one of these devices. There is a lot of conflicting and confused information regarding their use. In this post I will simply describe the internal workings of a common electronic transformer and try and clear up some of those loose ends of information that are regularly ducked by many vendors, resellers and to a certain extent the manufacturers.

Difference FAQ between ELCB, RCCB, RCBO and RCD

I was looking at, "Google Webmaster Tools," relating to this blogsite and noted that there was a very large number of queries which followed the format of: "difference between blah and blah" which related to an article I wrote What are ELCB, RCCB, RCBO and RCD's?.

While I didn't specifically write my previous post as a direct comparison, I can understand why it appears to be popular for this particular type of comparison query, as it contains an explanation of what these components are. I thought in this post I would give a brief direct explanation for that particular query type, which also includes a specific link to the original previous post for a clearer understanding of the components.  As this is intended as a pithy article I have assumed that you understand what the various acronyms mean. If you don't know what the acronyms mean then hit the included link and go to the original article for a clear explanation.

Circuit analysis of typical electronic transformer

Self-starting half bridge oscillator schematic

In this post I will go through the analysis of the design of the basic electronic transformer commonly used to provide the 12v power for halogen lighting.  Specifically the design of the common self-starting half bridge oscillator circuit.  I will not go into the actual calculation of values of the components but more why the circuit is arranged as it is and the purpose of each component within the circuit.  Looking at the final schematic of the circuit is quite daunting but it's really an elegantly simple circuit to explain. Understanding this will open a world to you, as you will see elements of this circuit built into so many other circuits, such as internally to drive LEDs and CFLs. By the end of this post you should be conversant in the design considerations of this particular circuit.