Here you can find the schematic of the KODAK Fun Saver single use camera. It is schematic of the new version of flash unit with LED charge indicator.

I'm trying to build macro flash using the flash units from the disposable cameras. I was searching the flash unit schematic on the net, but I found only the older units with neon charge indicator. All nowaday units have LED indicator, so I have disassembled one to draw its exact schematic.

It is unit from the KODAK Fun Saver camera, but very similar schematic is used also in other brands of disposable cameras (at least Fuji).

As you can see the circuit is very oversimplified to use the minimum number of cheap parts.
   

!!! But even such a simple circuit can produce VERY DANGEROUS VOLTAGE using only single 1.5 Volt AA cell !!!
!!! It can kill you or at least cause very painful burns on your fingers !!!
There are about 300 Volts on the main capacitor when charged and flashlamp fire electrode voltage is about 10000 Volts.
So if you plan to do something with such flash units, be very careful!

• Energy stored in the main capacitor (295 Volts): 3.5 Jouls
• Guide number ISO 100/f=30mm: 10