**4.3 Construction of thermocouple circuit**

The thermocouple wires (Type E) made of different metal alloys (Nickel-Chromium copperconstantan) is joined together by soldering. The number of thermocouples required to generate an output voltage of 15V is required. Knowing the output voltage of one thermocouple (type E) given as 153mv (0.153v), dividing 15 by 0.153 to give 98.04 = 98 junctions. There are six modules with 15 junctions each (Fig 9). These thermocouples were joined together in series to form cascaded thermopile consisting of a number of thermocouples.

Fig. 9. Thermocouple solar panel

The construction of the solar power module was simple and convenient employing modular approach in which the entire system is divided into modules. The design is to generate high voltage, thus the cells are connected in series in the module. The voltage is a function of the cell's physical composition, while the amperage is affected not only by the area of the cell, but also by the amount and intensity of light falling upon it.

Fig. 10. A section through the solar panel

For high amperage, the cells must be connected in parallel. The net voltage is the sum of the individual voltages in the cell. Increase in the voltage and amperage output of the thermocouple cells depends upon the mode of connection in the module. The efficiency and power output requirement is determined by the power output of one thermocouple given by the equations above, the number of thermocouples in series, and the surface area of the solar cell were thus determined.
