Turbine-electric transmission enters a turbine, where it expands down to the exhaust pressure, producing a shaft work output in the process. The exhaust is fed into the power turbine used to power an output shaft for whatever desired application. The power turbine is also connected to the electric generator, which converts mechanical energy into electrical energy. The electric generator driven by the power turbine charges the battery needed in order to drive the motor that supplies compressed air into the combustor. During cruise speed the electric motor does not have to be functioning, only the gas turbine engine is required to continue
Electric potential energy time-invariant electric fields. The electric potential energy of a system of point charges is defined as the work required assembling this system of charges by bringing them close together, as in the system from an infinite distance. ^\mathbf{r} q\mathbf{E}(\mathbf{r'}) \cdot \mathrm{d} \mathbf{r'}</math>, The electrostatic potential energy can also be defined from the electric potential as follows: The SI unit of electric potential energy is the joule (named after the English physicist James Prescott Joule). In the CGS system the erg is the unit of energy, being equal to 10 J. Also electronvolts may be used, 1 eV = 1.602×10 J.