Reverse Engineering a Chinese flashlight

[Nexo]

Hello everyone!

This is my first post and I'm a newbie in the ellectronic's world so please, go easy on me. 

I took apart a Chinese flashlight and started to Reverse Engineer its circuit in order to learn more about circuits.

This part is the AC-DC converter of the flashlight and it looks like this:



The red and black wires goes to the positive and negative of a battery that looks like this:



And this is the schematics that I tried to make:



I think there is something wrong with it because, as you can see, R2 and the led are connected to the point 1 which has AC current, ¿right? ¿Shouldn't it exploit or something like that?

I'll add more questions in a few minutes.

Thanks in advance!

[Nexo]

Anyone?

[MK14]

Hello everyone!

This is my first post and I'm a newbie in the ellectronic's world so please, go easy on me. 

I took apart a Chinese flashlight and started to Reverse Engineer its circuit in order to learn more about circuits.

This part is the AC-DC converter of the flashlight and it looks like this:



The red and black wires goes to the positive and negative of a battery that looks like this:



And this is the schematics that I tried to make:



I think there is something wrong with it because, as you can see, R2 and the led are connected to the point 1 which has AC current, ¿right? ¿Shouldn't it exploit or something like that?

I'll add more questions in a few minutes.

Thanks in advance!

What do you mean by "exploit" ?

Do you mean explode ?

If you do, it should be fine, because if you carefully analyse the circuit, you should be able to see that the rectifier diodes, only allow the current to get in one direction as regards that LED.  In the other direction, both sides of the LED (marked as point 1 and + on your schematic sketch) will be approximately at the same positive potential (give or take a diode drop), so no problem.
Only when point "1" becomes negative, will the LED get much current, and light (presumably it is an AC/Mains on LED, and is wired that way so it does not empty/drain the battery when not charging).

I don't like the fact that the mains input (AC) does not appear to be isolated, and there is no transformer. Be careful.

[imidis]

I can't be of too much help, it's an interesting circuit and confuses me.  See a lot of similar circuits on the cheap ebay stuff big clive does, with the bridge rectifier, capacitor, discharge resistor, and usually a couple other resisters in there as well and smoothing cap (for lights).
 Seems to be the cheapest way for them to convert ac/dc, although not the safest.

My newb questions, whats R2 for? surge?

And must be some circuitry in the battery?

[Brumby]

The capacitive dropper is not one that gets my vote of confidence - mainly because of safety.


Sometimes it is easier to remove reverse biased diodes from the picture....

Here are two versions of your diagram - one for each half cycle of the AC input: