The electricity generator (1) comprises a microcombustor (2) provided with a fuel injector (3) and acting to produce at an exhaust outlet (5) a flow of exhaust gas in plasma state comprising positive ions and electrons separated from one another, and a conversion device (6) coupled to the outlet (5) of the microcombustor (2). The conversion device comprises an electrically insulating duct (7) coupled to the said outlet (5) of the microcombustor (2) and provided in its initial portion (7a) with separation and capture electrodes (13,8;18) for capturing the negative charges (electrons) of the plasma in such a way that downstream the plasma comprises only positive ions (I). After the initial portion (7a) the duct (7) has an intermediate portion (7b) provided with an outer cladding (12) of conductive material insulated from the plasma, the ends of which are connectable to a load(L). In operation the flow of positive ions in the intermediate portion (7a) of the duct (7) electrostatically induces in the conductive cladding (12) a negative charge which propagates in the cladding (12) along the direction of flow of the plasma in the intermediate portion (7b) of the duct (7) thereby generating a flow of electric current in the load (L). <IMAGE>
