Performance improvement of regulator rectifier for 2-wheeler engine with respect to increase in power demand with upcoming stringent regulations in emerging market On two wheelers magneto generate either single or 3 phase AC power and regulator rectifier unit (RRU) do regulated rectification to charge the battery. In order to face the requirements of 2-wheeler engine with respect to upcoming stringent regulations like EFI, ABS, AHO in emerging markets like India; vehicles are demanding more electrical power from batteries. This demands higher power from magneto hence regulator rectifier unit (RRU). Higher output power forces challenges on regulator rectifier unit in terms of size, power dissipation management and reliability. In this paper how performance of RRU improved with MOSFET based regulator rectifier are discussed in comparison to silicon controller rectifier (SCR) design. The motivation of MOSFET design is described as well as the thermal behaviour and temperature coefficient performance of RRU with test result. The second topic discussed is how the MOSFET based RRU design help to improve performance by respecting form factor and total power dissipation compare to SCR based design.