THERMOELECTRIC FLASHLIGHT

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

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

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

Peltier tiles

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

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.

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

Battery free flashlight

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