This is the typical non-isolated AC/DC converter that by its nature, can pose a severe shock hazard. The largest parts are the 10K ohm, 5 watt resister and the .22 mF 250 V capacitor.
The image of the 10K ohm resister is greatly enlarged. 
“It is the knock-off counterfeit chargers that do the voltage drop with transformerless circuits using resisters, capacitors and diodes that are the problem. It is a circuit that is basically a voltage divider that uses a capacitor instead of a resistor to takes the 120 VAC from your wall and divides it down to whatever voltage you want. They may be cheap to build, but pose a shock hazard if a line voltage surge causes a critical capacitor to develop a short.”
I don’t buy this part. It would not be cheaper to build, and it would have to be huge. At 60 HZ, it would take a 20uf capacitor to pass an amp of current. 22uf is the size of a run cap on a small blower motor, and there about $10 each.
Resistors would be more expensive and would have to dissipate about 100 watts or so.
This is the typical non-isolated AC/DC converter that by its nature, can pose a severe shock hazard. The largest parts are the 10K ohm, 5 watt resister and the .22 mF 250 V capacitor.
The image of the 10K ohm resister is greatly enlarged.