Thermocouples operate on the principle that when two dissimilar metals are joined, a predictable DC voltage will be generated that relates to the difference in temperature between the hot junction and the cold junction (Figure 8). Electrons flow from negative polarity to positive polarity. To obtain more electric energy from a generator, the prime mover must supply more mechanical energy. Off-grid solar systems use solar panels to produce DC electricity, which is then stored in a battery bank (, The battery or voltaic cell converts chemical energy directly into electric energy (, Heat energy can be directly converted into electric energy by a device called a thermocouple. "@id": "https://electricala2z.com", It is summarized by talking about volts (V), which is equivalent to joules between coulomb (J/C).