1. THERMOELECTRIC FLASHLIGHT

2. Human body voltage
Human harness chemical energy to create electrical energy
Electric impulse created by our hearts is just,electricity
The scienctists says we are like 100 watt walking bulb in aspect of human energy
Our body radiate 5.7mW/cm²

3. Thermoelectric effect
Thermoelectric effect is direct conversion of temperature differences to electric voltage and vice versa
Seeback effect
Peltier effect

4. Peltier effect
The peltier effect is the presence of heating or cooling at an electrical junction of two different conductors.
When the current is made to flow through junction between two conductors,heat may be generated or removed at the junction
Q=(𝜋𝑎−𝜋b)i

5. Peltier tiles

6. Low voltage oscilator
Operating electronic circuit below 1 volt is a real challenge
For Low voltage devices the dc-dc converter is needed to boost the voltage to some reasonable level
The heart of this converter is an oscillator
Zero threshold voltage n-channel FET

7. Boosting the voltage
Dc cannot be multiplied but if it changed to ac,the voltage can be stepped up with transformer.
boosting the voltage is necessary because we need ample amount of voltage to turn on the led lights
Thus the step up transformer is used.

8. Physical flashlight design
The peltier tiles are mounted inside the cylindrical pvc tube.
Air flowing through the pvc pipe nd around the aluminium tube cooled the flashlight

9. Battery free flashlight

10. Advantages and limitations
Do not use batteries
Do not use toxic chemicals
Save the cost of batteries
The only limitatiion is its need for at least 5 degree tempreture difference to provide usable light