Joule Thief - DIY Micro-power Generator 250 MV

This is low voltage Joule thief experiment tested on micro-power source as low as 250 mV. Common Joule Thief usually required at least 650 mV so i was making some research if it can go lower than that. The purpose of this circuit coincide with my initial research on energy harvesting project to power up smaller applications.

In this video demonstration the component involve is only the coupled Inductor and green LED. You can find all the spec and circuit schematic diagram can be found by in the YouTube video descriptions. Some ideas you can expand from this circuit is harvesting RF signals, sound, vibration, etc to powerup LEDs. There are plenty more you can think of.

The component required in this circuit is very simple as follows

1. N851 NPN transistor

2. Coupled inductor 8.3 mH - this inductor is salvaged from faulty computer power supply

3. Wires

4. Adjustable mini-power supply (optional) - I am using this so be able to test the circuit at various voltages and behavior. You can use dead battery around 500 mV to 600 mV is fine.

Note: The coupled Inductor has two winding coil - 1 winding is clocked wise and the other is anti-clocked wise. Refer to the diagram below.

1. Connect one end of the first winding to the other end of the second winding and connect to the positive end of the power source.

2. Still on the first winding coil connect the other end of it to the collector of the transistor and also the positive terminal of the LED

3. Then the second winding connect the o