Thermocouples can be found at specialized retailers like Omega or online platforms such as eBay. While they can be made easily using two different metal wires joined together, their effectiveness as a power source is minimal, typically only capable of powering small devices like quartz clocks. A thermopile, which consists of multiple thermocouples arranged to increase voltage, can be created by alternating wires between two temperature sources. Visual aids for constructing thermocouples can be found online, but for significant power generation, alternatives like Peltier devices are recommended. Overall, thermocouples are more useful for temperature measurement than for generating electricity.