Current from thermocouple (T/C)
Be careful here, you might be the victim of a classic illusion of electrical engineering! Thermocouples do not "produce" or "generate" a voltage, as many books, on-line tutorials, magazine article, and well-meaning EE savants will consistently suggest. 

The temperature-dependent voltage you measure as the "output" of the thermocouple  is actually the difference of voltages produced by the two individual wires that  make up the thermocouple. Each wire produces a voltage (potential difference) from one of its ends to the other end, which is temperature dependent. This voltage is called the "Seabeck voltage". You don't need two wires to produce it just one! 

The Seabeck voltage is very tricky to measure because you have  to connect the  voltage  measuring device between the two ends of the wire producing/exhibiting the temperature dependent voltage. There are two problems: A) the measuring device changes the temperature of the end of the wire  to which it is connected, &amp; B) the wires of the measuring device also are subject to Seabeck  voltage effects. (Yes, copper wires produce a Seabeck Voltage, if the ends of the copper wire are held at different temperatures. Which t hey inevitably are because the meter mechanism or circuit is typically at a different temperature than the ends of its probe wires.) The measurement can be made with an ordinary DVM, but the set-up is very critical, and you won't get an actual reading of the target wire's Seabeck Voltage. The voltage reading you get from the DVM will only allow you to calculate the Seabeck voltage produced by the target wire.

Back to the thermocouple: In Ancient Times (1800's) the early EE geniuses figured out a way to coax the Seabeck Voltage out of the wire so it could be measured with early electromechanical meters (such as a galvanometer). They did this be using two wires composed of two different metals,  having two different Seabeck Coefficients (essentially volts/degree F), and thereby producing two different Seabeck voltages. It's the difference  between the Seabeck Coefficients of the thermomcouple's two wires that "produces" the "output voltage" you think you are  measuring from the thermocouple. 

The junction of the thermocouple does NOT produce the  voltage. It's not a "little battery", nor is it a "chemical reaction" caused by the junction of the two dissimilar metals, nor is it a semiconductor-like effect as is found in diodes and transistors. All of these  common analogies have caused generations of EE's to be  mislead as to the actual operating principle of thermocouples. 

Further, there are several other thermal-electric effects that occur simultaneously in the thermocouple mechanism that muddy the visibility of the Seabeck Effect. These are the Thompson Effect, the Peltier Effect and Joule heating. It's a miracle  that the Ancient Ones were able to figure  this all out with their primitive measuring instruments, but they did even if it took them several decades to do it.

Get yourself a good book on thermocouples and study it carefully to learn the real story of thermocouples.

BTW, there are a  number of illusions EE are forever falling for. My favorite is that red, green and blue light combine to make  white light. You've seen the experiment with the color filters, right? It's an optical illusion, which has fooled millions into accepting the  false conclusion that red_+ green +_blue = white.