NOVELTY - The photovoltaic solar cell (14) has contact (48) which connects the negative type or n-type sides of all of the junctions in parallel, and the other contact (50) which connects the positive type or p-type sides of all of the junctions in parallel. The doped regions of one conductivity type are regions of polycrystalline silicon fill extending into the semiconductor substrate (40), while the doped regions of the other conductivity type are doped regions of monocrystalline semiconductor substrate material. The substrate includes silicon or germanium.    USE - Photovoltaic solar cell for use in photovoltaic solar concentrator.    ADVANTAGE - Ensures that very little electrical power is required by the feedback control circuit since the circuit can be formed as a complementary metal-oxide semiconductor (CMOS) integrated circuit (IC) and since the piezoelectric actuators are voltage-operated devices which draw very little electrical current. Maximizes sunlight-to-electrical energy conversion efficiency by locating the first and second energy storage capacitors in a feedback loop around an operational amplifier which operates as an integrator. Reduces cost and simplifies assembly of the photovoltaic solar concentrator by allowing the molded unit to be snapped onto the substrate. Minimizes any lateral movement of the legs while allowing the legs to move in a direction substantially perpendicular to the substrate to tilt each lens 16 as needed to maintain the sunlight incident on the solar cells by using truss. Protects the light-reflective coating during handling of the lenses and insertion of the lenses into the tilt plates, while facilitating attachment of the lenses to the tilt plates since the recess or protrusion can be formed in the protective layer rather than in the lens so as not to impair the performance of the light-reflective coating.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic cross-section view of a transverse-junction photovoltaic solar cell.    Photovoltaic solar cell (14)    Semiconductor substrate (40)    Light-absorbing regions (40')    Passivation layer (42)    Contacts (48,50)    Sunlight (100)