photovoltaic cells can be used in handheld calculators
photoelectric_cell is transducer. calculator is computer. photoelectric_tube is laboratory_equipment. calculator is electronic_device. photoelectric_tube is tube_tangible. solar_cell is photovoltaic_cell. photocopier is electronic_device. multiplan is very_sophisticated_calculator. rtv_graph_visualizable is graph_visualizable. photocopier is machine.