Hello there everybody!! I was just planning to make a Small Thermoelectric couple. Will it work if i twist together the ends if 1 Cu wire and 1 Fe wire alternatingly And then heat the joints only? How many will be needed for generating 3 volts (50'C) and how long can it power the small led?

Thanks in advance for your help!!

 

Read up about thermocouples.

http://en.wikipedia.org/wiki/Thermocouple

http://www.allaboutcircuits.com/vol_1/chpt_9/5.html

Typical voltages are 50μV/°C

At 50°C - 25°C you will get about 1mV.

Hence you will need about 3000 junctions to get 3V.