Question: I have this circuit from a flashlight that runs an LED with just 2xAA batteries. Initially I thought it used a boost converter or a joule thief but when I opened it up I found that it did not. It depended merely on the 3V those two Alkaline or Zinc Carbon cells output in series to light up the LED at it's minimum voltage at 3V. Problems arise when the voltage of these primary cells drop after a while making the light very weak.

So I decided I want to modify it and make it run on two NiMh cells at 2.4V. I have attached the circuit below. Can I add components at just these 2 green points to make the joule thief work? Also there is not much space inside the flashlight to place a toroid, just enough space to squeeze a transistor and a couple of tiny components. I hear there exists Joule thief that uses discrete axial inductors and or ceramic caps?

[![enter image description here](https://i.stack.imgur.com/Q9igX.png)](https://i.stack.imgur.com/Q9igX.png)

Update:

Here is the latest Schematic. There is an additional point where I can add a component, that is the resistor point. I can de-solder the resistor (orange point) and add a component there if needed. The green points remain unused so anything can be added there.

[![enter image description here](https://i.stack.imgur.com/92gyv.png)](https://i.stack.imgur.com/92gyv.png)

Answer: 
[![enter image description here](https://i.stack.imgur.com/nzjyw.jpg)](https://i.stack.imgur.com/nzjyw.jpg)

TI.com suggests this solution. They have complete BOM and layout. Good luck.
Not sure I can answer your question of how to put a Joule Thief in your project. But I did find a [Joule Thief on Amazon](https://rads.stackoverflow.com/amzn/click/com/B01GEUNBPU) that, when it was available, might have fit. Even though the product is currently unavailable, I included it here because many people don't know how small a Joule Thief can get. This is a single inductor Joule Thief with a 490uH surface mount inductor.

The size of the board is small, at 10mm x 16mm. The inductor is the first component on the left, right next to the input (Power) terminals.

The ones I purchased worked fine. I simulated this circuit with two 2N2222's and a 1nF cap. I think I've seen this schematic design elsewhere on the web, but I don't remember where.

[![picture of a small all-surface-mount single-inductor Joule Thief populated circuit board.](https://i.stack.imgur.com/Jvfi6.png)](https://i.stack.imgur.com/Jvfi6.png)