mobile charger circuit working

[Bhavesh Gupta]

here is a mobile charger.i am trying to understand working of it for my project..plz anybody help me
**broken link removed**

 

[Audioguru]

The schematic in black is a simple crude circuit. Crude means cheap with poor performance and probably poor reliability.
It is a single transistor oscillator driving the transformer that gives its positive feedback.

 

[betwixt]

Agreed - and although I haven't simulated it or done calculations, my first impression is that 10uF/50V capacitor may not be polarized correctly. The problem with the circuit is it has no feedback from the output connections to correct the voltage if it is wrong or changes under load and it has no protection if something breaks down, in fact it would be extremely dangerous if for example the transistor went short circuit. I very much doubt it would meet even the most relaxed EMC testing.

The schematic below it, apart from being drawn badly, is completely wrong and will cause damage if built.

Brian.